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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 13701 to 13750:

  1. Climate change and wildfires – how do we know if there is a link?

    Perhaps I should ask the question another way. Polls say that a little over 50% of the people accept that humans contribute to global warming. Yet IMO far fewer than 50% of the general public are modifying their lives to acknowledge the reality of climate change. For people who already acknowledge climate change as real and our contribution as key, do these extreme weather events move them to start taking stronger action?

  2. Climate change and wildfires – how do we know if there is a link?

    Evan, I think people directly experiencing extreme weather first hand would mostly increase their acceptance of climate change science, especially warmists and fence sitters. I'm assuming here they are convinced the weather is getting more extreme or have seen data to that effect. Once the threat becomes real and perhaps painful, it clears the mind.

    I dont think it would harden anyones attitudes against climate science , unless they are really deep in conspiracy ideation and think its the government altering the weather, in order to bring on one world government . And yes, I have seen comments like this, but it cant be that many people.

    Of course even quite dramatic change probably won't increase acceptance among many of the denialists either, because they just rationalise it away with claims that climate changed before, the data is fake, its just weather. My guess is it would change maybe about half their minds at best. 

    Needs a poll or survey.

  3. Climate change and wildfires – how do we know if there is a link?

    nigelj @5

    That really seems to be the case.

    We had a fairly wet spring and early summer with few wildfires, we were well below the average until recently. The weather warmed up in early July and things dried out. Then we had a series of thunder storms come through that ignited a large number of wildfires. Over 400 in one outburst from what I recall.

    And now because smoke covers so much of the entire region, after the latest thunder storms it is very hard to detect new fires.

    2018 Wildfire season BC 

    "In fact, lightning has already sparked more than 1,300 wildfires in B.C. this year, which is more than any year since 2009. That number is likely to increase as the extended weather forecast calls for continued hot and dry conditions, with the risk of thunderstorms in some parts of the province."

  4. Climate change and wildfires – how do we know if there is a link?

    For those reading and writing comments here a question. Do you think people experiencing extreme climate-related events like wildfires, droughts, and floods firsthand increases their acceptance of climate science or hardens them against it? I'm not offering an opinion, just asking.

  5. Philippe Chantreau at 14:15 PM on 17 August 2018
    Climate change and wildfires – how do we know if there is a link?

    I think that's only part of the story Nigel. In BC, a major factor is the biotic stressors, many of which have been inked to climate change.

    www.mdpi.com/1999-4907/8/8/280/htm

  6. Climate change and wildfires – how do we know if there is a link?

    Doug_C, @4, I might have part of the answer as to why Canada is experiencing more forest fires. Its related to more lightening strikes. Climate change is leading to thunderstorms moving northwards more into regions like Canada due to climate change according to this article.

    I was simply curious as to whether climate change would lead to more lightening strikes as a general rule, and  I did a google search, and came across that article. However it appears that its not certain that climate change would cause more lightening strikes for the planet as a whole. Some studies say it will and some don't. Here and here.

  7. Climate change and wildfires – how do we know if there is a link?

    It's sobering, my brother and his family were evacuated from our hometown for almost a month last year and he wasn't sure if there was going to be anything to go back to. He and his wife were the last car out heading north from that city with flames burning on both sides of the road.

    He's a 30 year veteran with BC Forest Service and has managed fire crews for years and has seen nothing like what is happening now.

    There were multiple fires started near where I live in mid July, hundreds of people a few kilometers to the north were evacuated and many homes burned. 

    There have been very few smokeless days for a month and last year was the same for most of the summer.

    How we are supposed to treat this as normal is completely beyond me.

  8. Philippe Chantreau at 10:44 AM on 17 August 2018
    Climate change and wildfires – how do we know if there is a link?

    Thank you for reminding us of that Doug. Man made dorders matter little to physics. With all the noise made about the California fires, we tend to forget the extent of the BC fires. Over 1.2 million hectares burned and 65,000 evacuees in 2017. Current year shaping up to be as bad.

  9. Climate change and wildfires – how do we know if there is a link?

    Whatever is happening we are getting hammered for the second year in a row in western Canada.

    The new normal is going to be hugely expensive in terms of fighting fires, loss of property and loss of resouces like the forests themselves that are burning up.

    BC Wildfires Map

  10. Humans are pushing the Earth closer to a climate cliff

    Mal Adapted @16, agreed carbon fee and dividend has to be the central policy for all the reasons you have given eloquently and in detail here and over at RC. (Sad that you know who doesn't get it). And Michael Mann also thinks a carbon fee is a potential solution.

    Although we probably have to solve various environmental problems in parallel, and they tend to mutually help each other in many cases.

  11. Humans are pushing the Earth closer to a climate cliff

    nigelj @ 4

    Reducing CO2 levels does mean we need to change our economic model towards steady state. Or at the very least we need to develop a system that grows in sustainable ways, and perhaps in the services sector, rather than being based purely on maximising resource extraction until nothing is left.

    I agree that the global economy is up against multiple planetary boundaries, and must eventually become steady-state. AFAICT though, the specific problem of anthropogenic global warming is comparatively easy: we 'merely' need to replace fossil carbon with carbon-neutral energy sources. That's already underway, driven to an extent by market forces in response to piecemeal government regulations and subsidies to promote 'alternative' energy. Collective intervention on larger scales is needed to accelerate the transition, by internalizing more of the marginal climate change costs in global prices for fossil carbon. It's not that radical an idea. YMMV, but I've made no secret of my support for a US revenue-neutral Carbon Fee and Dividend with Border Adjustment Tariff.

    Once transferring fossil carbon to the climatically-active pool is no longer cost-effective, we'll have bought time to work on all the other problems.

  12. Humans are pushing the Earth closer to a climate cliff

    nigelj @ 4

    I firmly believe that we are already living far past what is sustainable for the environment over the long term.  We are consuming the world's resources far faster than is sustainable. Moving to adopting a steady-state economic model is imperative if we are ever to adapt to the restrictions that climate change and the enviroment as a whole imparts upon us.

    Will we be able to act in time and reduce CO2 sufficiently? I very much doubt it. Our brains and our sociities are just not set up right to make the logical deductions to arrive at the solutions we need to reach. I don't want to be a party pooper, but that's just the way I see it.

  13. Humans are pushing the Earth closer to a climate cliff

    Bob, if you want a closer statistical look at NA snow, try here and especially here. Note especially spring and summer trends. Couple of things to think about it. As the earth warms, the atmosphere holds more water. If the warm air goes somewhere cool (up, towards poles etc), then it rains or snows. If it is cold enough to snow, then likely snow volume will increase. Come spring, (which is happening earlier), then you have snow cover influenced by two constrasting factors - more than usual amounts of snow to melt against warmer than usual temperatures to do the melting. Extent of snow cover does affect albedo, but the climatic effect is not much in winter (especially in high latitudes) because duh, there isnt much sun. Snow persisting through summer is much more important. Indeed the transition to an ice age happens when orbital wobbles result in cold summers at 65N and a persistance of snow. Right now, we are having very hot summers not cold ones.

    Looking a real trends in NH snow cover (see here), I dont see anything encouraging at all. It is downward. Nor is there is anything unusual historically about two years of increasing snow cover.

  14. Climate change and wildfires – how do we know if there is a link?

    Informative article. Southern Australia has been experiencing a drought and high temperatures and serious bush fires recently, associated with persistent anticyclonic conditions. This is in the middle of Winter! 

    Drought conditions in southern Australia and the associated persistent anticyclones has been linked to climate change here.

  15. Humans are pushing the Earth closer to a climate cliff

    Bob Hoye @10

    We are not in a cooling trend in North America, globally we are in a warming state of climatic transition which results in a disruption of local weather patterns.

    You just have to look at the amount of heat that is constantly being added to the Earth's surface through the mechanism of radiative forcing from things like the massive emission of carbon dioxide by human activity.

    Fortunately we have a meter for that located on this very page.

    2.646 billion atomic bomb quivalent heat units have been added to the Earth since 1998 alone. Most of that absobed by the oceans in a band 30 degrees on both sides of the equator. A place where ice and snow cover is not growing.

    Here in BC ice and snow cover is also not growing we are witnessing a rapid loss of alpine glaciers in British Columbia.

    Near total loss of glacial ice expected in BC, Alberta by 2100

     

    We did have greater than average snowfall here last winter resulting in much deeper snow packs. But this is duirng the winter months when insolation is at its minimum here. Snow falls here later in the year and melts sooner. 

    Resulting in a greater and greater occurance of catastrophic flooding.

    Record flooding in southern BC

     

    I see nothing to be encouraged about by the highly chaotic weather conditions we are being subjected to here in western NA or the increainsly catastrophics impacts of fossil fuel generated climate change.

    The Earth is not cooling based on almost all the evidence, it is warming at a rate that is overwhelming most natural mechanisms to adjust in a way that will mitigate catastrophic impacts like the loss of coral reef systems.

    https://www.nytimes.com/2017/03/15/science/great-barrier-reef-coral-climate-change-dieoff.html

    Personally I have rarely seen the Sun in the last month and am glad that the large wildfire 3 kilometers to the north of my home has been put out. But much of this province is on fire with huge wildfire complexes that are joining together into incredible firestorms that cannot be fought. The same is happening right now in California. The smoke from BC reaches halfway across the continent and is causing unhealthy air conditions as far away as Manitoba.

    BC smoke blankets Southern Manitoba

     

    "Smoke from more than 500 wildfires burning in British Columbia has reached Manitoba prompting Environment and Climate Change Canada and Manitoba Health to issue a special air quality statement for the southern part of the province."

    Far from being encouraged, for many of us the experience is of being part of a very large scale and long term disaster movie where the conditions become increasingly hostile.

  16. Humans are pushing the Earth closer to a climate cliff

    While we continue to warm the atmosphere with CO2 emissions melting ice will continue. Basic physics. It may bounce around a bit from year to year but that is all.

  17. Humans are pushing the Earth closer to a climate cliff

    Bob Hoye @10, increasing snow and ice cover over two years is not a trend, or even change as such in any fundamental sense. It is weather and normal short term cyclical variation. Any increase in ice less than 10 years in duration can be dismissed as temporary natural variation. Read the IPCC reports.

    Remember the so called pause? The denialists were telling us the "warming trend" was over, this was "change", the models were wrong, an ice age was immenent. No I said, its natural variation and it will not last. It came to an end abruptly over the last 4 years in dramatic fashion. 

  18. Humans are pushing the Earth closer to a climate cliff

    The diagrams are illustrative and the part about ice or snow surface reflecting heat could be at an interesting juncture.

    The snow and ice cover for the Northern Hemisphere is published often. (I wish it was every day). Last year, the cover was above the high-side of the standard deviation band through the melt season of August and September. It remained above into October. And then for this year it was above begining in April. This begins the window of maximum energy being received at the Earth's surface. And the reflecting surface was greater than the year before.

    So far into this August, it has remained above the deviation band.

    While two seasons in a row does not constitute a trend, it represents a possible change. Particularly, with the Danish Met Institute's chart of temps "North of 80", which has been below the mean line through this melt season.

    Typically, this one gets below freezing at around the third week in August. And then when it is night all day there is little energy to reflect back into space.

    Over the two seasons, this is encouraging.

  19. Humans are pushing the Earth closer to a climate cliff

    ubrew12 @7: Wili's last quote from the OP:

    "What we are hoping for now is enough wisdom and will to at least stop short of going off these cliffs."

    You excluded "...and will" from your comment. Wisdom coupled with a will to act on it is absolutely necessary in mitigating and adapting to man-made climate change.

  20. Humans are pushing the Earth closer to a climate cliff

    If you're going to run into a brick wall and there's nothing you can do to prevent that, you need to prepare for the crash while applying the brakes. No matter when you apply the brakes the outcome will be better. But it does not mean you can avoid crashing.

    CO2 concentrations are accelerating upwards, not just going up. We can talk mightily about staying below 2C, but when we see that we are going over, it's time to prepare for what comes next, while we keep putting on the brakes.

    The problem is that our foot is still on the accelerator.

  21. Humans are pushing the Earth closer to a climate cliff

    wili@6: "What we are hoping for... is enough wisdom... to... stop short of going off these cliffs"  Jesus, friend.  Consider the words you just wrote.  'Enough wisdom' should have already stopped us well short of those cliffs.  Nope, not an alarmist, we'll muddle through.  But Earth's biodiversity is well and truly f000ed, and we should grant ourselves the right to say so.  We need to call out the fact that MAGA comes at a cost: the wholesale screwing of any part of this globe that isn't covered in MAGA.  No, if you're out there in the 'great unknown', you're not MAGA, you're a waste dump, as Turkey just found out.

  22. Humans are pushing the Earth closer to a climate cliff

    An important quotes from the full Guardian article: 

    "the time frames in the study suggest theres still much to be gained by keeping emissions under 2 degrees"

    "we don’t know how long they will take to tip"

    "it is far too late to avoid all climate change – it is already here.

    What we are hoping for now is enough wisdom and will to at least stop short of going off these cliffs"

  23. Humans are pushing the Earth closer to a climate cliff

    nigelj @1.

    I agree, there is a lot of reason to be concerned but this should motivate us not immoblize us.

    There are constant technological developments that give us options that didn't exist previously.

    Battery technology is rapidly maturing and with things like large scale redox flow batteries and solid state lithium metal batteries we can now plan electrical grids based almost entirely on intermittant sources of energy like wind and solar and can begin a phased movement to a transportation model based on electic power from those low carbon renewables.

    Three battery types in large scale grid storage

     

    Solid state lithium metal battery

  24. Humans are pushing the Earth closer to a climate cliff

    Reducing CO2 levels does mean we need to change our economic model towards steady state. Or at the very least we need to develop a system that grows in sustainable ways, and perhaps in the services sector,  rather than being based purely on maximising resource extraction until nothing is left.

    I think a steady state economy is inevitable sooner or later anyway. Take a look at gdp growth trends here and notice the falling trend over the last 40 years in developed countries, despite multiple tax cuts, a huge expansion of the money suppy, quantitiave easing, low interest rates, and endless stimulatory policies. I think anyone who believes high rates of gdp growth are possible in western countries anymore is delusional or will only achieve them very short term, and at the cost of huge debt levels and massive environmental damage.

    Developing countries are a different story. They have room to expand because of market demand for basic essentials of life. But they will reach a plateau eventually like western countries.

  25. Humans are pushing the Earth closer to a climate cliff

    With several nonlinear positive feedback loops potentially adding to global warming its going to be very difficult to predict the extent of warming we will see, or the size of any rise in sea level over the next 80 years. All the more reason for us to limit the amount of CO2 that we release into the atmosphere.

    It's not really a case of it being too late to do anything, as if we stopped CO2 output now it would have a sigificant effect on curtailing the amount of warming we will see. Given the human race's ability to obfuscate about our addiction to the fossil fuel drug that we have, it's more a case of us being unwilling to tackle the problem and to meaningfully reduce our CO2 output in the time we have before the positive feedback loops kick in.

    Reducing CO2 levels to the degree that we need to means that we will have to change our economic models from expansionist to steady-state Herman_Daly_thinkpiece. Something I don't think that politicians in most countries have the will to do yet alone the ability to achieve. 

  26. Humans are pushing the Earth closer to a climate cliff

    Through fossil CO2 emissions, people have driven a water vapor increase that triples the warming effect of the CO2 alone.   This should have served up an early warning that Earth's mysterious feedbacks won't magically resolve themselves in our favor, as we unnecessarily party our way through uncharted waters.

  27. Trump reignited his war with California, but his Tweet got burned

    Bob, you might also want to look at the graphs here to put 1930s in perspective with current temperatures. That the effects are so bad is due more to improvements in farming practise, irrigation and other technology.

  28. Trump reignited his war with California, but his Tweet got burned

    The charts dont tell all the story. The other side would be chart of $ investment in fire suppression and control. I think the forest service in US was created in 1930s in response to some big fires. If that hadnt resulted in change, then it would have been big waste of money. Much more interesting is change since 1970 when infrastructure for forest management is relatively constant but climate is changing.

    Fires are taking place despite huge increase in fire-fighting technology, investment and understanding on fire suppression. I would expect if temperatures increase, then the amount of investment is also going to have a dramatic increase.

  29. What does ‘mean’ actually mean?

    I really enjoyed Kevin's introductory statistics in the Climate Science Denial 101 course. Very stimulating.

  30. What does ‘mean’ actually mean?

    Kevin  Cowtan is very good  at explaining things and making it accessible. I only know part of this math but could get the general idea of where he was going. 

  31. Humans are pushing the Earth closer to a climate cliff

    The multiple tipping point  scenarios should have anyone worried, however the good news is the time frames in the study suggest theres still much to be gained by keeping emissions under 2 degrees. I get tired of the doom mongers claiming it's too late to do anything.

    However a study shows Antarcticas eastern glaciers are melting as well as the western glaciers, so are probably on the way towards a tipping point.

  32. What does ‘mean’ actually mean?

    A basic requirement for a good statistical analysis is that every member of the population being examined has an equal chance of being chosen in the sample you take.  In this case, each point of longitude/latitude would be the population.  Since sampling at such points around the poles is less likely, the various estimates have to be made with a single point near the poles being taken as the result for the points not sampled.  Not perfect but a pretty good first approximation. 

  33. Philippe Chantreau at 23:26 PM on 15 August 2018
    Trump reignited his war with California, but his Tweet got burned

    I wonder how that all looks if considering also British Columbia and Alaska. The past 2 years have been very bad in BC, all years since 2010 have had bad fire seasons. Limiting to the US is not very informative. The atmosphere doesn't care one bit about man drawn boundaries.

  34. Trump reignited his war with California, but his Tweet got burned

    Well, the USDA has a chart for the contiguous states that begins in 1916 and records a huge peak in the mid-1930s. Of course, with that exceptional drought and heat.

    The "Great Falls Tribune" of July 23, 1933 records that the acreage being burned each year is at "41,000,000 each year". There is a scan of the actual story.

    The recent burn rate is about 20 percent of the highs clocked in the 1930s. Included was the number in many millions of board feet, but if I go back to the article, I'll lose what I've posted so far.

    The chart above, the very top one shows the very high numbers recorded in the 1930s, which heat and drought I hope never return.

    Bob Hoye

  35. Flaws of Lüdecke & Weiss

    This is pretty close to a submission that got trashed for many of the same (but not all) reasons at Climate of the Past

    https://www.clim-past-discuss.net/cp-2014-149/

    Moderator Response:

    [PS] Link activated. Please use the Link button in the comments editor to create links yourself

  36. Trump reignited his war with California, but his Tweet got burned

    We can also let the past be our guide to the future, provided we understand the context of our modern era vs that of the past:

    "The data do suggest however that even modest increases in temperature and drought (relative to those being projected for the 21st century) are able to perturb the level of biomass burning as much as large-scale industrialized human impacts on fire.

    More dramatic increases in temperature or drought are likely to produce a response in fire regimes that are beyond those observed during the past 3,000 y."

    And

    "Based on the fire data alone, the levels of burning during the 19th and 20th centuries are not anomalous; there were times (i.e., the LIA) when fire was as low as it has been over much of the 20th century, and times when it was as high as during the 1800s, as around 50 to 1 BCE. When climate is considered however, the past approximately 150 y (i.e., back to 1850) are remarkably anomalous. Although the current rate of biomass burning is not unusual (even allowing for post-1980 CE increases in burning such as in ref. 3), it is clearly out of equilibrium with the current climate.

    Our long-term perspective shows that the magnitude of the 20th century fire decline, while large, was matched by “natural” fire reduction during cold, moist intervals in the past (e.g., LIA). Current fire exclusion and suppression however, is taking place under conditions that are warmer and drier than those that occurred during the MCA, which calls into question their long-term efficacy."

    Marlon et al 2012 - Long-term perspective on wildfires in the western US
    PNAS
    doi: 10.1073/pnas.1112839109

    US Wildfires last 3,000 years

    Larger version of image

  37. Pollution is slowing the melting of Arctic sea ice, for now

    Yup, M.Sweet@4.

    But digging coal provides jobs! But at the cost of about 1 person for every seven job-years. The math: About 70,000 people have jobs directly mining coal. So 70,000 people work for a year, and 10,000 other people downwind die. Hire 700 more for a year, 100 people die.

    Two miners working for 35 years each, for 70 job-years, and 10 people die. And as a bonus, the Earth gets warmer!

  38. Trump reignited his war with California, but his Tweet got burned

    Bob @5 - no, accurate forest fire records are not available that far back.  In fact they're not very accurate prior to 1983 (see Zeke's post).

  39. wilddouglascounty at 00:06 AM on 15 August 2018
    Climate change science comeback strategies

    Regarding the first strategy, and addressing the "climate change has happened before without fossil fuels in the mix," I like to use the analogy that pretty much everyone can relate to: car troubles. If your car doesn't start, it could be for a whole host of reasons. This is because the car is a complex system with many inputs and outputs, so if the car is out of gas, has a dead battery, has run out of oil or coolant, or has a mechanical failure, it won't start.  In a similar fashion, the complexity of global climate has many inputs and outputs, so that in the past orbital dynamics, volcanic output and natural emissions/absorption of greenhouse gases have driven the observed changes. This time, we've definitively isolated the release of greenhouse gases at a rate that is faster than the earth systems can absorb it as the source of the changes we are observing.  You can ignore the science if you want, but it's kinda like ignoring your mechanic when he says that it's a dead battery and so you put more gas in the tank and expect the car to start. Furthermore, if your mechanic says that he replaced the battery so it should be fine and it still doesn't start, it's time to go to another mechanic.

  40. Trump reignited his war with California, but his Tweet got burned

    The charts are fascinating.

    The first chart of area burned runs from 1965 to recent.

    The second is of California's temperature history starts in 1895 and runs to recent.

    To be thorough and consistent, the comparison should include the history of area consumed by wildfire from the same approximate date. That is to say about 1895. It is available.

  41. Welcome to the Pliocene

    Just to clarify my rushed comment @18 where I said that sea level rise of 20 m would take thousands of years as ice melts slowly, but I mentioned periods of rapid sea level rise in apparent contradiction to this. The periods of rapid sea level rise appear to relate to very strong regional warming in critical areas of the Americas,  and destabilisation of glaciers causing their flow to speed up.

    Meltwater pulse 1a has its own wikipedia entry and it's quite good.

  42. Trump reignited his war with California, but his Tweet got burned

    Beyond me how someone like Jones avoid defamation/libel court action.

  43. Welcome to the Pliocene

    @ Johnboy - the fastest major sea-level rise that we know about was the one approximately 14,500 years ago, known as Meltwater Pulse 1A. This involved up to 20m change in up to 500 years - or roughly 4m per century: however, its detailed progrssion is still the subject of much research.

  44. Trump reignited his war with California, but his Tweet got burned

    Ubrew12, I came across this recently. Facebook has banned Alex Jones. Great, facebook is a private organisation and can do this. It's also effectively now in the business of news, and needs to maintain a certain standard.

  45. Trump reignited his war with California, but his Tweet got burned

    So what is causing the White House ignorance  about climate change and forest fires etcetera? Its all certainly a political war against environmentalists, and the other side of politics, and I agree loyalty to the Trump team is seen as more important than the facts.

    Imho Trump is also clearly out to destry rivals like Obama, and will go to extremes to do this no matter how much it hurts America. The GOP seem hypnotised and powerless to deal with this, or perhaps they feel the same. I can understand the GOP concerns about the economy and big government to a point, but its now out of control, and their denial of the science is just so totally risible.

    The northern hemisphere heatwave is genuinely as scary as hell. If warming has disrupted the normal pattern of the jet stream, it could be permanent wouldn't it?  Forest fires would be significantly more frequent. However we are still at least able to stop the pattern getting even worse if sensible climate policies are adopted.

    We have put a lot of faith in planting trees as a carbon sink. It looks like increased wildfires are working against this, almost like a positive climate feedback. The only solution will be better management of the forests, better fire breaks, and please people stop voting for complete fools who don't know when to stop tweeting.

  46. Welcome to the Pliocene

    Johnboy, in very broad brush terms, the change from glacial (22k ybp) to warm (10k ybp) is 4-5 degree C. ie 0.04 degree per century compared to around 0.6-0.8C per century now. However, that is a very smoothed rate of change in a somewhat spiky record. There were short periods of faster warming/cooling especially in polar/temperate regions of both hemispheres (but not necessarily in phase), eg Younger Dryas, Antarctic Cold Reversal event etc. However, unlike the transition from glacial, the rate of forcing is also much higher as DB has said.

  47. Welcome to the Pliocene

    On the topic of adapting to SLR, I came across this 2014 PNAS paper, Coastal flood damage and adaptation costs under 21st century sea-level rise. From the abstract:

    Without adaptation, 0.2–4.6% of global population is expected to be flooded annually in 2100 under 25–123 cm of global mean sea-level rise, with expected annual losses of 0.3–9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US$ 12–71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure.

    Can I interest anyone in an un-elevated bayfront house in Hampton Roads?  My brother expects to sell his (so far) perfectly good house as a teardown, and the new owners to build a new, elevated one. He's adapting to SLR by moving 15 ft. uphill!

  48. 2018 SkS Weekly Climate Change & Global Warming Digest #32

    Michael Mann is exactly right. Imho we have to balance both environmental and economic affairs. Nobody will die without owning the latest $1000 smartphone with its "face recognition and reimagined camera".

  49. Welcome to the Pliocene

    Johnboy, my understanding just as a layperson (more or less) is the pleocene was about 2-3 degrees warmer than today, with sea level about 20 M higher, but this developed over thousands of years. CO2 concentrations were similar to today and changes were slow.

    We are forcing change more rapidly, but its a case of how this works out in our reality. On business as usual CO2 emissions we are on track for 4 degrees by 2100 which are Pleocene like temperatures, but because some of the positive feedbacks are so slow, over  millenia we could experience temperatures in excess 4 degrees ultimately. Even if we dont hit 4 degrees by 2100 we will get there eventually  as positive feedbacks work.

    So huge areas of our planet could move to a tropical climate and heatwaves would be on top of that and probably in some of our lifetimes or over the next few centuries after this .

    It would take thousands of years for sea level rise to increase to 20M. Ice melts at a certain rate. We would adapt but there is obviously huge loss of land area and soils, and soils take practically forever to develop.

    However the thing that gets my attention is evidence within these early climates like the pliocene and others is that there were relatively short periods of rapid warming of several degrees per century, and rapid sea level rise of 2-5 m per century, something we would have huge difficulty adapting to. There's also evidence of things like super storms and abrupt climate shifts in the atmospheric and ocean circulations which have huge regional implications.

    If sea level rise was 20 metres over  thousands of years we would adapt to some extent, but rapid sea level rise of more than 1 metre per century, for maybe a couple of centuries  would be catastrophic and much harder to adapt to. Theres already evidence of a speeding up of ice melt in Antractica as a whole, including both east and western glaciers.

    The pleocene world.

  50. Trump reignited his war with California, but his Tweet got burned

    Alex Jones' term 'InfoWars' describes what Trump is doing here.  In War, truth is the first casualty.  Once the fossil-fueled rightwing disinformation network has convinced voters in critical states that 'there's a war on for your mind' (as Jones puts it), then all information becomes a weapon and either acts to defeat the enemy or weakens 'our side'.  Trump is lying, knows he's lying, his troops know he's lying, and the 'enemy' knows he's lying.  It doesn't matter, the information either hurts the other side or it doesn't, and if it doesn't, then it hurts your side.  Consider Trump's claim as a 5 year old would: do rivers, in fact, naturally flow to the sea?  If not, are salmon communists, lying about their progeneration requirements in order to impose One World Government?  You 'have to be carefully taught' to look past the obvious absurdity of what Trump is suggesting CA do, and see his tweet for what it is: a salvo, fired in the face of the enemy, and nothing more.

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