Arguments
Recent Comments
Prev 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 Next
Comments 6701 to 6750:
-
michael sweet at 03:45 AM on 27 October 2020Climate's changed before
A long time ago someone at SkS suggested that sea level in the Pacific ocean peaked about 3-5,000 years ago and then went down about 1.5-2 meters. This explained how atolls formed and why they have coral rock above current sea level.
I do not see this change in MARodgers graph at post 843 but it seems consistant with his post at 850. Is sea level change the current understanding of how atolls came to be above current sea level? (Most atolls in the Pacific have 1-2 meters of coral stone at their core which cannot form above sea level. Sea level could have changed more than that.)
-
One Planet Only Forever at 03:18 AM on 27 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
nigelj,
The following is my current understanding of the problems faced by efforts to develop sustainable improvements for the future of humanity. Better understanding a problem, and the desired outcome, is one of the most important steps in developing sustainable solutions, as every Engineer is very aware.
Regarding reactions to climate science and climate change information and misleading claims, a major difference between the USA and NZ is probably that, relative to NZ, the USA has more powerful wealthy people who have their wealth and power because of fossil fuels. They would lose status if the changes of how people live that are required to limit the climate change harm done to future generations are actually achieved. Increased awareness and understanding of the need to meet the Paris limits makes these powerful wealthy people more likely to lose their status. And that threat of losing their perceived status causes some of them to mentally 'lose it' and double down on harmful misleading marketing rather than striving to honestly change to be less harmful and more helpful.
Other possible reasons for the difference regarding harmful populism in the USA and NZ could be:
- The USA is the least Socialist of the supposedly more advanced nations. I use 'supposedly' because it highlights that 'impressions of advancement' may be misleading. Increased wealth or increased technological development that does not result in sustainable improvements of the living conditions for the poorer portion of the population is not 'advancement'.
- The USA, since its foundation, has been a nation of Anglo Saxon Colonists pursuing ever expanding Superiority for 'Their Tribe' relative to all 'Others' (the reason I pointed to "White Fragility" as a book to read). Books like "The End of the Myth" by Greg Grandin present an accurate and unflattering history of the formation and expansion of the USA (violent disregard for Others is a powerful part of the USA's history). And many Americans are still powerfully motivated by their collective lack of social development on acceptance of diversity and the related need to systemically more equitably treat the diversity of humanity.
- In the USA the 'pursuit of freedom' has been about the more freedom for powerful wealthy property-owning people (with property including Other people) to become more powerful and wealthier (small government having no role in regulating economic activity, not limiting the harm it does). It includes protection of the ability of likely unjustly acquired wealth to be passed to children who may be even less deserving of having that wealth and power. The wealthier a person is the more helpful and less harmful to Others that person needs to be, or the advancement of society is slowed or reversed.
- The USA has a 2 party system which makes it easier for the greedy and intolerant people to gather together and claim that 'The Other is the enemy'. And the history of the USA explains why the 2 Parties in the USA substantially share the objective of protecting the wealth of the wealthy. However, currently the Democrats are leaning towards being more Socially Sharing and Caring due to their party including the Social Democrat thinking. Multi-party systems may make people more aware of diversity rather than seeing things as Black-White Us-Them. In Canada there is only one party heavily focused on promoting greed and intolerance, the merged Right-Wing Conservatives. There used to be a Progressive Conservative Party that was centrist, but it disappeared when it merged with social conservatives and increased appeals to greed (which used to be in fringe parties). The inability of the hard Right-wing Party to get along with a diversity of Other Parties may make more people aware that it is the uncooperative party that is the problem, rather than a 2 party system where 'The Other' can always be blamed.
Another difference between the USA and NZ is that the Separation of Church and State has been removed by the current Republican pursuit of popular support from fundamentalist religious groups, because there is such a large population of fundamentalist evangelical religious people (and those people appear easily inclined to believe conspiracy theories about 'Those Others - Their Enemies').
A related difference between the USA and NZ may be that the USA has also amplified the power of wealth in government. It is clear that democracy requires a separation of Wealth and State (read Thomas Piketty's "Capital and Ideology") so that the State can act as the Responsible Governor of what is going on to limit harm done and help develop sustainable improvements for the least fortunate.
In summary, Social Democracy that effectively limits the influence of Religion and Wealth on the actions of Government may powerfully inoculate populations against populist autocracy. Note that anti-Socialism is part of the misleading marketing attacks by the greedy and intolerant portions of many populations that have joined forces to try to win the power to do as they please. Selfish people are more inclined to be harmful to Others, and less inclined to be helpful to Others. They easily dislike the idea of being 'forced to share and care by Government'. Any government that would do that is part of the 'Others'. They want the freedom to 'Win higher status any way they can get away with'. To them 'Harm Done is justified by Benefits Obtained'.
Closing back to climate change and climate science. The belief in conspiracy is strong in people who have developed preferred beliefs that are contradicted by expanded awareness and improved understanding of how to be less harmful and more helpful to Others. To maintain their perceptions of status and related beliefs, they accept anything that appeals to them, including the ability to declare themselves to be the Victims - of conspiracies, which requires the belief that there is no Objective Reality as a basis for Common Sense, every belief is equally valid - because of the barage of falsehoods they have developed a liking for but have been unable to make sense of.
-
Bob Loblaw at 01:16 AM on 27 October 2020Climate's changed before
Eclectic:
A direct link to MA Rodger's figure is:
I notice that it is formatted to display is as a webp object, which might be breaking things for you if that format is not supported in your browser. It seems to be a Google format. YOu might try dropping the "as=webp" part.
As for isostatic rebound: keep in mind that it is a local effect. The crust is depressed where ice weighs on it, and rebounds when ice is removed. Areas around the ice do the opposite - they flex upwards when the ice pushes downwards, and move back down when the ice is removed. Think of what happens when someone places an object on a waterbed.
Interpreting sea level changes due to glaciation is rather complex, and evidence is difficult to find.
-
Eclectic at 00:14 AM on 27 October 2020Climate's changed before
Correction :- not Peltier (2002) , but Khan et al. (2015) as per link in #850
-
Eclectic at 00:05 AM on 27 October 2020Climate's changed before
MA Rodger @850 ,
sorry, but your diagram [relative sea level map] is not loading for me. (And yes, Nigelj, I have tried 3 computers!! ) I will take a stab, and presume the diagram is from Peltier (2002) .
If I understand you correctly, then relative sea level (disregarding the "short term" alterations from thermal volume effect and total mass change) during the Holocene interglacial . . . ought to receive a major influence from isostatic rebound of subpolar land regions, as well as from the more general land "rebound" secondary to oceanic siphoning. And both of these rebounds should produce a late-Holocene fall in relative sea level (i.e. measured at shore-lines). Perhaps excepting special cases like southern Britain.
To all of which, we can add in some extra fall secondary to late-Holocene cooling that reduced ocean temperatures and also deposited more ice on land ~ an amount of ice presumably rather less than the 30-meter deposit I mentioned in last paragraph of #849 . . . (a deposit too marginal to really decrease the land rebound).
I guess the whole question comes back to the nett result on "Mean Sea Level", from all these various factors. In view of all the difficulties in local measurement of millennial changes, I am not surprised by the scatter of results from different studies on this topic.
Almost - but not quite - it is enough to feel some sympathy for that remarkable outlier, the (recently) late Dr Moerner.
-
MA Rodger at 20:27 PM on 26 October 2020Climate's changed before
Eclectic @849,
In the past, I do recall SLR free of significant tectonic movement being claimed as a good indicator of global SLR and that it usually concerns Australian data but I'm not sure such claims usually attach to late Holocene SLR. Lewis et al (2008) and indeed Lewis et al (2013) and Lewis et al (2015) are concerned with the late Holocene and more so the Australian record than establishing a global record. And their findings are not so clear cut although a significant drop in sea level post-7,500y bp has been established. The 2013 paper concludes:-
"A clearer understanding of past sea-level changes and their causes is urgently needed to better inform our ability to forecast future changes. A concerted effort is required ... to address the issues of whether there have been oscillations of the sea surface and if so, of what magnitude. The pattern and rate of fall from the Holocene highstand to modern levels, and of the contributions of the various factors to this change, both global ‘eustatic’ or ‘steric’ components and local geophysical, tectonic and land instability issues also need to be addressed."
The work to unravel the late Holocene global SLR record is far from complete and I see no evidence of the Australia (Oceania) data providing a short-cut to providing a conclusion. Thus, the conclusion from, for instance, Khan et al (2015):-
"Far-field Relative SL records exhibit a mid-Holocene highstand, the timing (between 8 and 4 ka) and magnitude (between <1m and 6 m) of which varies among South America, Africa, Asia, and Oceania regions."
And on the reasons:-
"The Relative SL signal of many far-field locations is characterized by a mid-Holocene sea-level maximum, or highstand, at the time meltwater production decreased. The fall in Relative SL to present is due to hydro-isostatic loading (continental levering) and a global fall in the ocean surface due to both hydro- and glacio-isostatic loading of the Earth’s surface (equatorial ocean siphoning). Perturbations to Earth’s rotation driven by mass redistribution also cause Relative SL changes in far-field regions to depart from the eustatic value. These processes occur during the deglacial period but are not manifested in far-field RSL records until the early to mid-Holocene because the eustatic signal is dominant prior to this time. Far-field locations are characterized by present-day rates of Relative SL change that are near constant or show a slight fall (<0.3 mm/a) in [rate of] Relative SL (Fig 1)."
-
takamura_senpai at 17:18 PM on 26 October 2020The Debunking Handbook 2020: Debunk often and properly
People say what is profitable/gainful, NOT they realy think. USA produce more CO2 than whole Africa + S America + ...much more, if we look on goods which USA consume. Latin America + half Africa + others is a USA colonies, so MUST produce huge CO2, they must supply USA with many things.
For example: Brasil paid > 1 trillion to USA in last 20 years, and debt is higher and higher - colony. -
nigelj at 15:49 PM on 26 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
OPOF, I have a copy of Post Truth, by Evan Davis so that is another one to add to the list.
Your explanations sound quite good, although I'm still puzzled why we haven't seen quite the same extent of problems in NZ, ( we have seen some and it is growing a bit) but it may partly relate to geography and size and location, in that we are very small and very reliant on trade and international alliances which does open the mind and make people more tolerant of 'foreigners' and international organisations, and very aware of what happens in other countries. Fake news and xenophobia finds it harder to gain traction in that sort of environment.
America is so large it's almost self contained, and certainly trades less on a per capita basis than us, all of which might create a little bit of a bubble where fake news can gain traction along with anti foreigner sentiments, and if you tap into that racial dimension with appropriate falsehoods and emotive rhetoric, you pretty much have people under your control. We have had politicians like that and our share of xenophobes, but they are getting less and less traction. It was actually a free trade agreement with China around 2006 that got us through the GFC, and people are grateful.
-
Eclectic at 13:34 PM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
RedBaron @22 ,
thanks for that info. I did see that a charge would not be made until 28 Oct . . . but I wasn't clear whether that applied only to donations which were in excess of the official target. The wording was a touch ambiguous ( I thought ). I am guilty of overthinking the wording.
BTW my original computer has still shown the defective pop-up window on the Experiment.com website. Perhaps my software is not as up-to-date as I had believed. All the same, it might be worth dropping a word to the site Administrator, to check that the donation "mechanism" is functional for a wide range of operating systems (both ancient and modern) ~ if such is possible in a secure way. Every fishing line should have a hook on it!
2nd BTW ~ and thanks, RedBaron, for the Widow's Mite tale you had mentioned earlier. No reply from Mr Keithy, I see.
-
One Planet Only Forever at 13:24 PM on 26 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
nigelj,
What is happening in the USA is a massive effective misleading marketing campaign that appeals to people who believe they should be masters of the world, or at least the masters of their part of the world, or at least the masters of what is believed in their part of the world (or more likely aspiring toward as much of the above as they can get away with).
Post-truth or some version of it is discussed in many books. And many of them were written decades ago about how Lenin and Hitler openly told falsehoods and bombasted their way to steamroll evidence-based understanding, common sense, out of the minds of many to establish popular belief in what they claimed.
The onslaught of nonsense that appeals to a gut-reaction, first impression, emotion-triggered type of response over-whelms the ability of many people to figure out what is actually verifiable common sense. People feeling a little less successful than they believe they should be are easily led to believe they are being cheated by 'Others'. And in the USA, white or english-speaking or evangelical-christians or men (or any combination) are feeling cheated out of their Perceived Right to forever continue, strengthen, and expand their rule over Others in their part of the USA, all of the USA, and around the world. And another group that is easily triggered is greedy people who want more status relative to Others any way they can get away with. That greedy group has figured out how to appeal to the first group to get more support for their fight against the rapid ending of fossil fuel use.
The first book I read about the attack on 'Reason' and 'Evidenced based understanding' was Al Gore's "The Assault on Reason". More recent books on the topic of post-truth include Masha Gessen's "Surviving Autocracy" and Michiko Kakutani's "The Death of Truth".
Other books about the current state of affairs in the USA include "On Tyranny" by Timothy Snyder, and "White Fragility" by Robin DiAngelo.
The problem is not because of Trump. The problem in the USA has been developing towards something like Trump becoming President for a while now.
-
RedBaron at 11:55 AM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
@20 Eclectic,
Your card won’t be charged unless the project is fully funded.
-
nigelj at 11:44 AM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Eclectic @20, I made a donation some hours ago and having read your comment I just checked my credit card account, and payment not registering either, so its probably a delay. I think it can take a day or two sometimes.
I'm a bit like Scaddenp, so a bit sceptical about the whole soils issue, but I think basically its because more information is needed, and experiments like this help. Its a worthy cause.
-
Eclectic at 09:01 AM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Nigelj @18 ,
thanks - I have now tried another computer, and possibly successfully!!
Mine is an all-Apple household, so I figured (in my klutzy way) that simply shifting to another Apple would make no difference. But quite wrong. The second computer brought up Scott's webpage, and the pop-up window this time appeared to be perfectly conventional & fully functional in accepting details (including credit card). So now I have donated - possibly. I say possibly, because Scott's webpage shows a coincidental contemporary uptick in his total . . . but my credit card account shows no deduction yet.
I shall keep an eye out - I hope it's just some electronic "lag effect".
-
scaddenp at 07:15 AM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
I should clarify that I am not in anyway involved in the experiment except as one of the donars. I have been very skeptical of the experimenter's claims made on this site in the past but the weight of evidence provided by him has convinced me that:
a/ should his hypothesis be correct, then his methods could make very useful contributions to mitigating global warming (with plenty of environmentally useful addition as well)
and
b/ this hypotheses has promising supporting evidence and deserves further experimental testing. The proposed experiment and the conditions of experiment.com should provide useful evidence.
-
nigelj at 05:07 AM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Eclectic, I just signed up for red Barons website ok. Suggest you try using another web browser or computer.
-
Eclectic at 22:33 PM on 25 October 2020Climate's changed before
MA Rodger @847 ,
thanks for that information. Re late Holocene MSL decline, I must confess I was relying on memory of seeing (several years ago) a graph of the Holocene highstand declining by 1-2m during the most recent 4-5000 years, as the global temperature reduced by around 0.7 degreesC. As you say, I might have been rather faultily recollecting something which lacked land "rebound" compensation.
On the other hand ~ a quick googling turns up SE Lewis et al. (2008) showing an eastern Australian fall in MSL of 1-1.5m over the period 7000-2000 BP. Eastern Australia (excluding Tasmania) had very little burden of ice sheet at the last glacial maximum (to rebound from) . . . and Australia has been tectonically relatively stable, as well ~ so it is a useful basis for Holocene MSL trends.
I think I may be misunderstanding your IPCC reference where: "Ocean volume between about 7 ka and 3 ka is likely to have increased by an equivalent sea level rise of 2 to 3 m." If the lagging effect of Holocene warming produced a likely 2-3m MSL rise over the period about 7000-3000 BP . . . is that inconsistent with a 1-1.5m MSL fall in the last 3000 years? [Assuming some fuzziness/uncertainty in the Lewis et al. dating]
As a matter of interest, I did a quick back-of-envelope calculation: indicating that for a 1m fall in MSL, the depth of ice on Greenland/Antarctica would need to increase by about 30m. This ignores oceanic thermal contraction and glacier expansion in non-polar regions.
-
MA Rodger at 19:50 PM on 25 October 2020Climate's changed before
Hal Kantrud @845,
There is certainly a timelag between temperature rise and ice loss and with big ice sheets the lag can also be big (but not necessarily). The current level of AGW is put at 1ºC and the sea level rise so far at 20 or 30 cms. Yet the anticipated sea level rise per 1ºC AGW is put at 230cm over a period of a couple of millenia. But additional to that 230cm/1ºC is Greenland which maintains its ice sheet solely becuse its summit is high up surrounded by cold atmosphere. It is anticipated that somewhere between 1ºC and 2ºC of AGW, the summit of Greenland's ice will drop into an unstoppable melt-out as the summit decends into warmer atmospheres, this adding a further 600cm to sea level over perhaps ten millenia. I say "unstoppable" in that it would require a return to ice age conditions to stop the melt and build the summit back up into colder airs.
Regarding the chopping down of woodland, this is globally not New World.
-
MA Rodger at 19:34 PM on 25 October 2020Climate's changed before
Eclectic @844,
I'm not sure where you get the metre drop in late Holocene sea levels. There have been dropping sea levels in some locations through the late Holocene but that is due to isostatic rebound caused by the redistribiution of mass - melted ice sheet flowing into tropical seas. The accepted wisdom as I understand it is still as per IPCC AR5 Ch5 5.6:-
"Ocean volume between about 7 ka and 3 ka is likely to have increased by an equivalent sea level rise of 2 to 3 m."
"For the past 5 millennia the most complete sea level record from a single location consists of microatoll evidence from Kiritimati that reveals with medium confidence that amplitudes of any fluctuations in GMSL during this interval did not exceed approximately ±25 cm on time scales of a few hundred years. Proxy data from other localities with quasi-continuous records for parts of this pre-industrial period, likewise, do not identify significant global oscillations on centennial time scales."
-
RedBaron at 19:07 PM on 25 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Keithy,
One of the donors lost her farm when the Russians annexed Crimea. As recently as 6 months ago she was struggling to avoid becoming homeless when Corona hit, having her whole family disrupted and nearly "refugee status" around Kiev, an already poor country before the war. And I never asked her for a dime, just showed her the work I am doing to help farmers back when I first designed this, before the corona delay. She told me back then she was almost in tears to think people she never even knew were working so hard to help people they don't even know. So clearly this isn't about being "rich". I was even embarrased that she donated. I wished she would have told me, so I could have stopped her. But you know how farmers are, stubborn to the core.
The whole point of a crowd funding science is to have lots of people donate really small amounts, so that no single person needs to dig deep at all. And then the science is open sourced for all to benefit. In this case there were a few bigger donors and I am eternally grateful and amazed. But that tiny donation from a displaced farmer who lost almost everything she owned so recently, touched me more than I have words to express.
I will bet my bottom dollar Scaddenp was just frustrated, as most of us here are, by the lack of people realizing how important mitigating AGW is.
My friend from Crimea knows first hand how quickly our lives can change through forces out of our control. I am pretty sure that's the sort of motivation the whole world needs to think about, as about 80-90 % of the World's population is in danger zones from unmitigated AGW, whether from coastal flooding, droughts and fires, or war.
There is another group of farmers that know all too well what's in store for us all. Maybe you heard of them?
The Ominous Story of Syria's Climate Refugees
So please don't be too hard on Scaddenp. We are all in this together.
-
Keithy at 17:20 PM on 25 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
@ 12: scaddenp, Who are you to be disappointed? The world doesn't owe you anything --> especially when you consider it gave you everything.
How ungrateful are you for being so rich by mistake?
Moderator Response:[BL] You are pushing the envelope in inflammatory rhetoric. Tone it down.
Skeptical Science is a user forum wherein the science of climate change can be discussed from the standpoint of the science itself. Ideology and politics get checked at the keyboard.
Please take the time to review the Comments Policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
-
Eclectic at 13:55 PM on 25 October 2020Climate's changed before
Hal Kantrud @845 , your first paragraph is crossed-up.
As the planet cools 0.7 degreesC during the past 5-ish millennia, more land ice forms, and so the sea-level falls. MA Rodger's graph (above) is a broadbrush illustration of sea-level, yet data fuzziness does not illustrate the small fall (roughly in the region of 1 maybe 2 meters in the past few thousand years).
As far as I have gathered, the broad scientific opinion favors a return to atmospheric CO2 level around 350 ppm. Incorporating carbon into deeper soil is a worth goal, but probably will be too slow (and limited) to achieve a negation of all the recent & continuing fossil fuel usage.
-
Hal Kantrud at 12:06 PM on 25 October 2020Climate's changed before
Thanks. To narrow down, the graphs show temperatures dropped during the last 6 millenia, while sea levels rose about 2m. One would think sea levels would rise, so is there a time lag working here?
CO2 increased during this period till the recent spike. There is no data on NH4 and SO2, but I thought this mix tended to prevent reflection of the sun's rays and thus increase temperatures.
I am not convinced that 'cutting trees' in the New World was as important a source of human CO2 emissions as the switch of grasslands from the production of perennial grasses to annual crop plants and domestic animals. Forest soils are notoriously poor in carbon and most is sequestered in the trees themselves, whereas perennial grasslands sequester most carbon deep underground while evolving in cycles of frequent fire and intense herbivory. Soils dominated by grasses have always been the first to be heavily exploited for food production ("the land of milk and honey") and were where our staple foods such as wheat, rice, barley, etc., were domesticated. So to seriously tackle the problem of high CO2 levels, it would be more efficient to seed perennial grasses, whose root systems remain the only viable net CO2 sink. Trouble is those areas are the source of most of our food!
-
Eclectic at 10:44 AM on 25 October 2020Climate's changed before
Hal Kantrud , I would like to add a few disparate points which may be of interest to you. (And you may already have come across some of them.) As always, I shall be grateful if MA Rodger (who is extremely well-informed on climate matters) sees fit to make any corrective comment!
1. The term "BP" / bp stands for Before Present, but does not mean "up until right now this year of [2020]". BP is a convention used by the paleo scientists to standardize the reference to past ages - whether centuries, millennia or mega-years [ma]. BP at point zero is taken as year 1950.AD
Some "contrarians" have not been aware of this convention (for instance the slightly-contrarian scientist Loehle has had to go back and correct some of his work, because he was initially unaware of the paleo convention).
Hal, this paleo convention is enormously important, since there has been a huge rise in global surface temperature since 1950. Even today, some Denialist blogsites are publishing graphs which misrepresent reality, and are showing a graph's final temperature as 2000.AD or 2010.AD . . . when the original graph only went up to 1950.AD . . . and worse, the denialists have sometimes doctored or airbrushed-out the most modern temperatures. Sometimes this deliberate deception is outright concealed - and sometimes the deception is camouflaged under the term "Adapted from [a certain scientific paper]" .
Another small point is that some of the ice-core temperatures are recorded up until around 1855.AD , since later/shallower levels of ice are unrepresentative of their ambient conditions.
[You will have noticed how almost all science-deniers are still falsely (and vehemently) asserting that both the Holocene Maximum and the MWP were hotter than 2000.AD and current years.]
2. The Holocene Optimum [sometimes called Holocene Maximum] was roughly 8000 years ago, but as MA Rodger rightly points out, the Maximum was more of a plateau of roughly 5 millennia. Over the succeeding 4 or 5 thousand years, the temperature has dropped roughly 0.7 degreesC as part of the background cooling which would eventually lead into the next glaciation. But AGW has intervened - with global temperature rising like a rocket in the past 100-200 years (dare I say like the end of a Hockey Stick?) Hockey Stick is yet another term which causes Denialists to choke on their cornflakes.
As a consequence of the natural cooling down from the Holocene Maximum, the global sea level has reduced by about 1 or 2 meters . . . and that fall should have continued onwards as we slide into the next glaciation. Except for the modern AGW-caused rise in sea level, a rise which is slow but accelerating.
3. Each glaciation cycle of the past 800,000 has been subtly different, owing to differences in the variations of the Milankovitch cyclings. That makes it difficult to predict when the next glaciation would have occurred in the absence of human influence. One figure I recall seeing, is the next chilly glaciation being due in roughly 16,000 years. So we humans have plenty of time to fine-tune our climatic effects before any threat of severe glaciation! (Some denialists maintain that the "New Ice Age" was due in a few centuries from now . . . and our anthropogenic CO2 has fortuitously been raised only in the nick of time... )
4. I won't comment on your point of interest about the New World grasslands. The changes there would be quite minor in the overall picture.
-
nigelj at 07:14 AM on 25 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
"We have the Trillion Trees program. We have so many different programs. I do love the environment (says Trump)”
Trump does not have a one trillion trees programme. America does not have a one trillion trees programme. Its all spin. Trump is just joining something called the "global one trillion trees initiative" which is funded by many countries. in terms of Americas contribution it mostly amounts to planting some extra trees in the USA on conservation land.
Its also "tokenism" because the actual planting plan in the USA is a small part of the solution to climate change. Politicians often have token programmes to try to keep everyone happy, things that sound nice and dont cost too much or ruffle corporate feathers. Some references on the tree planting programme here and here.
We have just had a general election in New Zealand. A centre left leaning Party won, and the centre right party lost in a landslide. The interesting point is the leader of the losing Party was a little bit like Trump in style and personality, although the policies were different except for her very dismissive attitude to climate change and other environmental problems. There is some good evidence that most people are not too impressed with her style (polling and commentary) and perhaps her position on climate change.
Given all this and other evidence, I doubt Trump would get more than 5% support in NZ or Australia. I simply dont understand whats going on in the USA, and how anyone could support a leader who has been so ineffective on really crucial things, and who gets so many facts wrong, regardless of whether the leader leans left or right.
-
MA Rodger at 22:21 PM on 24 October 2020Climate's changed before
Hal Kantrud @842,
To address your three requested points of clarification/confirmation.
(1) The only actual continent-sized ice sheet is Antarctica and that remains unaltered in size through an interglacial and through a glacial maimum. The glacial maximum see the growth of ice sheets across the northern half of N America, Greenland and N Europe. The Greenland ice sheet has survived the present interglacial but was melted out in the previous one.
The impact of small wobbles in global temperature is not significant within this process as the temperature change is small and it doesn't last very long. The ice melt is a slow process. Thus, while global temperatures stopped rising 10,000 years ago, the melt continued strongly for a further 2,500 years and less strongly for another 4,000 years, this shown by the sea level record.
(2) Your timings are a little off. After the Holocene peak temperture (best considered as a plateau 10,000y to 6,000y bp), global temperature has been dropping but only to the equivalent of 11,000y bp. 13,000y bp would have you back in the Younger Dryas event when it was very cold.
(3) The CO2 record from ice cores does show previous interglacials with CO2 (& CH4) levels falling quickly from the peak of the interglacial. This is not the case for the present interglacial when CO2 (& CH4) levels are shown to rise not fall. This has led to some interesting work setting out the idea that the activities of mankind are responsible for this early rise, for CO2 perhaps dating back to 8,000y bp (& 5,000y bp for CH4).
While this work remains speculative, the CO2 (& CH4) levels through this interglacial would act to slow the drop back into a glacial maximum.
The unprecedented CO2 levels likely now top the CO2 levels seen 3 million years ago (this was back when N America was joined S America at Panama and initiated the Arctic ice) and are thus uprecedented in 13 million years, thus back to a time when weathering of the newly-formed Himalayas caused reducing CO2 levels.
....
And addressing your main question which concerns the CO2 levels of the last few centuries rather than those of the late stone age because any increase pre-industrial cannot be the result of fossil fuel use.
According to the Global Carbon Project, the anthropogenic CO2 emissions since pre-industrial amount to some 650Gt(C) of which 450Gt(C) results from fossil fuel use and 200 Gt(C) due to Land Use Change, but note this is mainly cutting trees down not "the conversion of New World grasslands".
-
Eclectic at 15:50 PM on 24 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Sorry, RedBaron, but I still can't access via Sign In. The pop-up window does not allow me access to email & password fields. Very strange.
I see at the bottom right corner of the [experiment.com] Home page there is a field where I can request the regular newsletter emailed - but I am not wishing to enrol for the newsletter.
RedBaron, you probably can't do anything to raise my IQ to something above moron status. But it may be worth your while to contact the experiment.com Administrator, to see if there is some attention needed to the pop-up window that I mentioned. ( I shall check back in a few days to see if the Home page has altered.)
-
Hal Kantrud at 13:23 PM on 24 October 2020Climate's changed before
Thanks. So we are in a period of the current Ice Age where continent-size ice sheets cover land at the poles. While waiting for the next Ice Age, we experience cooling periods, (phases) but these are too small to significantly increase the size of the continental ice sheets. Does this imply that the warming periods or phases will not significantly reduce the size of the ice sheets?
Am I correct in reading the graphs that during the Holocene, Earth reached peak temperatures about 8000 YBP and has since cooled down to temperatures reached about 13,000 YBP, but during the last 200 years has spiked to levels far above those observed during the Holocene peak?
Can I also say that atmospheric CO2 levels followed an opposite pattern, slowly increasing during the last 8000 years, only to spike upwards during the last 200 years to unprecedented highs?
My main question concerns the latter. What portion of the recent spike in CO2 can be attricuted to the conversion of New World grasslands to agriculture and pasturage and what portion can be attriubted to the increased use of hydrocarbons worldwide?
-
RedBaron at 04:18 AM on 24 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Eclectic,
I am not exactly sure what you mean, but if you follow the page you will see this at the top right: Discover Start a Project Sign In
Click "Sign in" and it will ask for an email and a password, or you can use facebook if you want.
Fill them in click log in and it will sign you in. Then you can go to my project and click "Back this project".
-
One Planet Only Forever at 00:57 AM on 24 October 2020What does the global shift in diets mean for climate change?
RedBaron@28,
Agreed. Pursuing Sustainable Development, which humanity needs to pursue in order to have a lasting improving future, aspires to develop the most sustainable ways of living. That involves doing everything more sustainably, endlessly pursuing better ways of doing things.
The less fortunate seldom have the luxury of choice and have limited ability to learn about their choices. The more fortunate have 'No Good Excuse'.
Differences in the impacts of the ways of growing different foods should be the basis for the choices that more fortunate people make. The more fortunate a person is, the more helpful and less harmful their choices should be required to be (the ball and chain of being more fortunate is the obligation to Be Better).
A related point is that unnecessary over-consumption, like eating more than 100 g of meat in a meal or eating meat in 2 meals a day, needs to be ended. The less fortunate have no role to play in that effort. That one is totally on the more fortunate. And the more fortunate a person is the greater the expectation, or requirement, for them to actually be Better Examples that way (that ball and chain of more responsibility for the more fortunate to be less harmful and more helpful).
-
Eclectic at 20:41 PM on 23 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Scaddenp, I wish to donate funds, but am running into an obstacle.
As a computer klutz, I don't recognize what I am doing wrong. There were some earlier problems I had, a couple of weeks back. But now that you have reminded [us] to donate, I find a new problem :-
when I click on the donating field, up pops a window with : "LOG IN"
plus [second line] : "Don't have an account yet? Sign up."
Unfortunately, the LOG IN [etc] announcement almost fully overlaps the first field below it - and I cannot access the first field. ( I can access the email field and the password field which are below that. )
Is there some extremely simple mistake I am making? Do the experiment.com people need to re-jig their layout? (Worse - are other potential donors getting frustrated and abandoning the attempt?)
[ Mine= ancient Apple desktop, but with up-to-date software, I believe. ]
-
scaddenp at 07:43 AM on 23 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Hm. I am disappointed with funding so far. This is an interesting experiment that deserves your support. Advertise it on your facebook etc. people.
-
RedBaron at 07:19 AM on 23 October 2020What does the global shift in diets mean for climate change?
Like most foods, rice is similar. It's not rice that is the problem, but how we raise the rice that matters.
The System of Rice Intensification (SRI)…
… is climate-smart rice productionIt's not meat that matters, but how we raise that meat. Rice, wheat, meat, timber, you name it. There are right ways to raise it and wrong ways to raise it.
“Yes, agriculture done improperly can definitely be a problem, but agriculture done in a proper way is an important solution to environmental issues including climate change, water issues, and biodiversity.”-Rattan Lal
-
One Planet Only Forever at 06:17 AM on 23 October 2020What does the global shift in diets mean for climate change?
nigelj@26,
I agree that lots of people 'rely' on rice for basic food needs.
I would say that the more fortunate people 'choosing' to eat rice may be more helpful regarding climate impacts, and other impacts, if they reduced their rice consumption and replaced it with lower impact alternatives.
With global population still increasing, increased areas for rice cultivation would be a concern from a climate and biodiversity impact perspective (and other impacts). And reducing the extent of areas already under rice cultivaton would, like reducing areas needed for cattle raising, be helpful from a biodiversity perspective.
-
RedBaron at 14:32 PM on 22 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
For those considering funding this trial, I thought it might be useful to post a more formal link to the hard science supporting the reprint of now defunct Australian Farm Journal article. Here you can find the methods, scope, and results supporting Dr. Christine Jones claim for a CO2e sequestration rate of 5-20 tonnes CO2e /ha/yr "under appropriate conditions".
The role of grazing management in the functioning of pasture ecosystems
And here is a published paper from the US confirming a similar rate.
I should caution though. While the first one did include both grazing alone and pasture cropping, the second by Teague was only comparing various grazing strategies and did not include any cropping at all, nor was it a long term study either.
Since I am cropping only and only simulating grazing with a mower and compost, I really don't know what the rate of carbon sequestration I will find will be at all. I am as curious as the rest of you. Also the scope of the trial I designed is quite limited. I designed this to be potentially useful for those farmers wishing to help mitigate AGW by changing agricultural methods and become eligible for carbon credit payments. So the audience I am mostly looking at is not PhD's, but just ordinary farmers. So my scope is very modest.
If funded of course all this and more will be added to the lab notes section.
I would think that it would take a much more expensive trial and a formal team of full time research scientists to follow up if the results I find are interesting and/or significant. But the results I find should be useful "in the field" for actual action mitigating CO2 rise in the atmosphere.
We will see?
And the link for those who haven't been there yet.
What is the rate a new regenerative agricultural method sequesters carbon in the soil?
-
Eclectic at 12:10 PM on 22 October 2020Climate's changed before
MA Rodger @835,
Thanks. Yes, I had heard that the "frozen Thames" events had occurred even during the Medieval Warm Period (though those are never mentioned by Denialists).
I was interested in the "meme" of Thames freezings being held up as an example of the world-chilling severity of the Little Ice Age. And as I was saying to Hal Kantrud (who seems just starting out on learning about climate science) . . . the main point to remember is that the LIA and the MWP were pretty small beer compared with earlier climate changes.
As you yourself know very well, the LIA is greatly misrepresented by the climate-science Deniers :-
(a) Firstly, they exaggerate its severity ;
(b) Secondly, they falsely claim that our modern rapid warming is (somehow) "just a rebound from the LIA" .
(c) Thirdly - with amusingly unintended irony - they claim that the huge temperature excursions of MWP & LIA make the modern warming look insignificant . . . and yet at the same time they claim that the planet's Climate Sensitivity is so very low that we need not be concerned about the "slight" warming effect of anthropogenic CO2 emissions. Superb!
MA Rodger, you might not have seen it . . . but on one of the Denialist blogs recently, a particular Denier asserted that (by his calculation) Earth's Equilibrium Climate Sensitivity was around 0.4 degreesC. Improving on that, he then (based on the negligibly-small rise in CO2 which he attributed to humans) calculated that, of the modern warming, only 0.02 degreesC was human-caused. To repeat: 0.02 degreesC. Not a misprint. (Ah, who needs to pursue comedy, when so much is freely available on the Denier blogs! )
-
Daniel Bailey at 09:20 AM on 22 October 2020Climate's changed before
Hal Kantrud, by definition an ice age is any period with continental-scale ice sheets on land (like now). Within an ice age are warmer periods called interglacials and colder periods, called glacial periods (or glacial phases). The Little Ice Age nor any cool episode in the past 13,000 years do not rise to the standard of a glacial phase.
(bigger image here)
As can be seen below, glacial and interglacial periods are self-evident:
(bigger image here)
When it comes to the modern warming forcing from human activities, it's already comparable to the warming which lifted the world out of the last glacial maximum 24,000 years ago to the height of the Holocene Climate Optimum 8,000 years ago:
"About 2.3W/m2 (from CO2), a few tenths more from CH4 and N2O.Anthropogenic GHG forcing is ~2 W/m2 (CO2) and ~0.5 W/m2 from CH4+N2O+CFCs.
So they are comparable - ice sheets were a bigger term in the deglaciation tho."
(source)
Humans are inducing a phase transition from an interglacial world to a no-glacial world. So we are ending the ice age itself.
-
nigelj at 08:30 AM on 22 October 2020What does the global shift in diets mean for climate change?
Wayne @24, I have no dispute with the studies you quote. And yes several things contribute to methane emissions including cattle and other animals, and rice paddies and leaking gas pipelines. The point is reducing red meat consumption is one of the easiest ways to reduce emissions.
Reducing areas in rice cultivation doesnt really make sense and just isnt going to happen. Billions of people are reliant on rice for basic nutrition. Red meat is a much easier target as its not essential in the diet and its such an inefficient use of resources. I think thats pretty much the essence of the issue.
-
Hal Kantrud at 08:10 AM on 22 October 2020Climate's changed before
Tom on the 19th. "Within each actual ice age there is a series of glacial periods and interglacial periods" Guess I took that to mean an ice age extends from one peak glaciation to the next. Perhaps you were referring to the 'surges' in glaciers during the peaks.
-
scaddenp at 06:55 AM on 22 October 2020Climate's changed before
"I see no dips in atmospheric CO2 following any of the world's worst pandemics"
Others disagree. See Ruddman and Carmichael 2006, vanHoof et al 2006.
Whether such short term effects like pandemics last long enough to affect climate is more debatable (Pongratz et al 2011)
-
Tom Dayton at 05:43 AM on 22 October 2020Climate's changed before
Hal Kantrud, you wrote "What threw me off was your statement that LIA's were glacial periods." Who stated that, where?
-
Postkey at 04:12 AM on 22 October 2020Is Nuclear Energy the Answer?
“Could Russia Floating Nuclear Plants Change World Economy?
By F. William Engdahl
25 November 2019While the EU and United States have all but abandoned nuclear energy as a future power source, with almost no new reactors being built and existing ones being decommissioned, Russia has quietly emerged as the world’s leading builder of peaceful civilian nuclear power plants. Now the Russian state nuclear company, Rosatom, has completed the first commercial floating nuclear plant and has successfully towed it to its ultimate location in the Russian Far East where access to power is difficult. It could transform the energy demands of much of the developing world, in addition to Russia. An added plus is that nuclear plants emit zero carbon emissions so that political opposition based on CO2 does not apply .“
-
Hal Kantrud at 03:54 AM on 22 October 2020Climate's changed before
I didn't say the 'wobbles' caused any LIA's. But the evidence seems to show "wobbles" are assoicated with Ice Ages. What threw me off was your statement that LIA's were glacial periods, hence my question about possible evidence of expanding ice caps during these periods.
It is interesting that the Holocene Macimum occurred about the same time as the dawn of agriculture and pastoralism, concentrated on the carbon- and nutrient-rich grasslands of the Old World. So perhaps the slow atmospheric CO2 buildup shown by the ice core studies could have been caused by such 'mining' of grassland soils, followed by the spike in CO2 during the Industrial Revolution as the grasslands of the New World suffered the same fate, aided by mechanical power rather than the draft animals of old?
-
John Hartz at 01:13 AM on 22 October 2020Is Nuclear Energy the Answer?
Recommended supplemental reading:
Regulators have approved designs for 12 small reactors to be built in Idaho, but opponents say the project is dangerous and too late to fight climate change.
Small Nuclear Reactors Would Provide Carbon-Free Energy, but Would They Be Safe? by Jonathan Moens, InsideClimate News, Oct 21, 2020
-
MA Rodger at 23:11 PM on 21 October 2020Climate's changed before
Eclectic @834,
Do be aware that London's frozen River Thames was a very rare event and if anything provides evidence against the Little Ice Age being something exceptional with reported freeze-ups occurring even during the Medieval Warm Period. There were perhaps only a half dozen Frost Fairs listed in the records and they stopped appearing, not because of warmer winters but because the old London Bridge was demolished and the river embanked.
Given such reasons for the absence of Frost Fairs since 1813, perhaps a better river to look for evidence of a Little Ice Age (or lack ofevidence) is the Rhine which is recorded freezing 14 times since 1784, the last time in 1963. Of those 14 freezes, most occurred well after any Little Ice Age with seven during the 20th century.
-
michael sweet at 20:36 PM on 21 October 2020Is Nuclear Energy the Answer?
Philippe Chantreau,
When I was young I believed the promises of nuclear engineers. After 45 years of following nuclear power I no longer trust their paper designs and promises of safe reactors. If they ever build a pilot plant we will see if their scheme actually works as they claim. Upthread I cite the French Nuclear Regulatory Agency which does not see safety improvements in these new designs and the Union of Concerned Scientists who fear that false claims of inherent safety will lead to removal of expensive safety features in reactors. There are reasons that they have not yet built even a test reactor or pilot plant after 13 years of work.
I note that NuScale is losing customers now that they are actually trying to build their reactors. The cost is too great. It is not clear to me if their reactor price has increased or if renewable energy is now so cheap that they cannot compete. Probably both.
Nuclear power is uneconomic. It takes too long to build. Even if they achieve their goals it will be 2050 before TRW reactors are ready for a large scale buildout. I see no reason to believe that reactors with complicated double cooling systems can control the problems of using liquid sodium in a cost effective manner. They have not addressed the problems of Abbott 2012. I am especially concerned about the extensive use of rare materials.
In a renewable energy world baseload power is very low value. Peak power on windless nights is most valuable. Current baseload plants are dinosaurs.
-
michael sweet at 20:03 PM on 21 October 2020All Renewable Energy Plan for Europe
A $20 billion plan (Guardian article) to build a giant solar farm in the Australian outback has been announced. Much of the electricity will be transmitted to Singapore to replace expensive gas generated electricity. I recently saw a description of a scheme to manufacture hydrogen using electricity from a giant solar array in Australia.
The price of solar power is now so much lower than fossil energy that this type of plan can make money. Hopefully more giant farms will replace current fossil generators. The Southwest USA has a large area perfect for this type of farm. Usable deserts exist in many locations worldwide. Existing gas generators can supply backup power at night while storage solutions are developed.
-
One Planet Only Forever at 15:03 PM on 21 October 2020What does the global shift in diets mean for climate change?
wayne,
Thankyou for re-presenting the rice example as a part of your thinking regarding this issue.
My comment is that the sustainability of all food production needs to be the objective. From a climate impact perspective the status quo plant and animal growth activity, not its expansion or other impacting things humans do to grow the food, is not an issue in the planet's surface/atmospheric cycle. The issue is human activity that is harmfully changing things like increasing ghg's in the atmosphere.
There have been many study reports regarding the ghg impacts of different types of agriculture. The general, and consistent or common, conclusion of those investigations appears to be as presented in this OP - reduced meat consumption and changes of how the reduced amount of meat is produced or obtained would be beneficial from a climate impact perspective.
My concern is the broader Sustainable Development Goals which include biodiversity loss and other harmful unsustainable impacts of human activity. Expansion of food production that negatively impacts biodiversity is also harmful and needs to be reduced.
It may be that rice and meat consumption need to be reduced, and for more reasons than the climate impacts. Rice has less nutrient value than potato. And over-consumpton of meat has serious health implications.
-
wayne19608 at 10:57 AM on 21 October 2020What does the global shift in diets mean for climate change?
Hi Rob @23 that's why I said it was a start :) and was just adressing the impact of rice cultivation. Do we not think that 22% and 11% methane contributions compare unfavourably with those of cattle?
Organisms vary in their efficiency of feed conversion. Ruminants or foregut fermentation is one of the greatest developments in evolution since it's arrival some 50 million years ago. The benefit and efficiency of this system can be seen in their almost complete dominance of the herbivorous meso/megafauna. Virtually all non-ruminants or complete hindgut fermenters have since that time faced extinction. Out of some 450 ungulates today only about 25 non ruminants survive.
See (Demment MW, Van Soest PJ (1985) A nutritional explanation for body-size patterns of ruminant and nonruminant herbivores. Am Nat 125: 641–672) for an explanation on the distribution and relative efficiencies of these different fermentation systems. Notice that non-ruminants are fermenters as well, just that one of the fermentation products ie., methane comes out the back instead of the front.
This does not just apply to different digestive/fermentation systems but the inputs and outputs themselves.
Feeding high nutrient/digestable feed to ruminants may result in lower enteric methane outputs (Boadi, D. A., Wittenberg, K. M., Scott, S. L., Burton, D., Buckley, K., Small, J. A. and Ominski, K. H. 2004. Effect of low and high forage diet on enteric and manure pack greenhouse gas emissions from a feedlot. Can. J. Anim. Sci. 84: 445–453.), but see their qualification and comparison to IPCC estimates
A concern when evaluating animal feeding and management strategies to determine greenhouse gas mitigation potential is that significant emission reduction in one part of the production system may be negated if emissions are increased in another part of the production system. Table 6 demonstrates that inclusion of whole sunflower seed in general resulted in significantly lower (P < 0.05) total daily emissions of CH4 and NO2 expressed as CO2 equivalents. The observed reduction in total emissions is attributed to a significant reduction in enteric CH4, which contributed 95 to 96% of the total non-CO2 emissions from the feedlot. Enteric emissions by feedlot cattle fed a typical barley-based finishing ration were 72% of that estimated by IPCC (Tier 1). Use of whole sunflower seeds in the high forage:grain diet resulted in even lower emissions relative to estimates. Similarly, manure pack emissions in the current study were approximately 50% of that estimated using IPCC (Tier 1) coefficients.
Indeed over 7.5 times more CH4 kg–1 dung (DM basis) was emitted from grain-fed compared to their hay-fed counterparts.
Jarvis, S. C., Lovell, R. D. and Panayides, R. 1995. Patterns of methane emissions from excreta of grazing animals. Soil Biol. Biochem. 27: 1581–1588
Thus the "thermodynamically impossible" comment, but it goes much further than that.
People do realise that sheep and goats are just small ruminants and cattle are just large ruminants. You can even have cattle and sheep that approach each other very closely on a size basis. On the basis of size alone one of the biggest thermodynamic constraints will be the surface area to volume ratio, smaller organism will be energetically less efficient than larger ones, "having to run all day just to stay in one place". This is literally highschool physics and biology.
Monogut organisms like ourselves and for simplicity sake chickens and pigs cannot handle the feed inputs that hindgut and forgut fermenters can, generally requiring higher quality feed from both a nutrient and digestive quality standpoint. But those feed inputs didn't arrive out of the blue, they required huge (relative) inputs and resulting outputs. By focussing on enteric emissions we are missing the forest for the trees.
I can deal with monogut efficiency and energy inputs/outputs of cash crops later as I am running out of time, but these conversations always remind me of how little people understand about their food whether it be wheat, corn, chicken or cows
-
Rob Honeycutt at 09:16 AM on 21 October 2020What does the global shift in diets mean for climate change?
Wayne... As far as I can tell, your statement "the math is wrong, that it is thermodynamically impossible" isn't supported by your references at comment #22.
Can you be a little more specific?
-
Eclectic at 09:12 AM on 21 October 2020Climate's changed before
Hal Kantrud, the planetary "wobbles" are much too slow to cause any brief effect such as the Little Ice Age [LIA].
Have a look at the PAGES 2K study.
Many people hear the name "Little Ice Age" ~ and combine it in their mind with old illustrations of Dickensian snow and London "Ice Fairs" on the frozen Thames, and suchlike Christmassy freezes.
But in reality, the LIA was very minor. Less than 0.5 degreesC colder than the usual background for the Northern Hemisphere, and more like 0.3 degreesC cooler for the global whole.
Even the Medieval Warm Period [MWP] was only around 0.3 degreesC warmer than the global historic background. Despite some of the trumpet-blowing about the MWP and the LIA, they were both pretty minor events overall. Their names do greatly exaggerate their size. And they are insignificant compared with the level of warmth of the Holocene Maximum (about 8000 years ago) and the even higher temperature levels of recent decades (which are around 0.5 degreesC hotter than the Holocene Maximum).
Prev 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 Next
