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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.

Recent Comments

Comments 6251 to 6300:

Daniel Bailey at 03:42 AM on 9 October 2020

What Tucker Carlson gets wrong about causes of wildfires in U.S. West

Philippe, repost away!

What's important is the public understanding of the science and that comes best with widespread dissemination.

Philippe Chantreau at 03:20 AM on 9 October 2020

What Tucker Carlson gets wrong about causes of wildfires in U.S. West

Daniel,

While wildouglscountry argument is not without merit, reducing you post to the descriptive of "impressive statistics" seems a rather underhanded way to belittle what is one of the most comprehensive examination of the problem I have seen. Would you agree for others to repost, copy/paste with proper attribution?

Doug Cannon at 02:40 AM on 9 October 2020

Berkeley study: 90% carbon-free electricity achievable by 2035

michael sweet.

I guess I didn't make myself clear. Of course we have to take into account the costs of global warming. But we can't lie to ourselves about the fact that decarbonizing will require a huge investment up front.

Don't just look at the video and its carefully couched claims. Read the report and the NREL references. They show the cost of wind at $25/Mwhr now, dropping to $15/Mwhr by 2035. The cost of solar at $20/Mwhr now, dropping to $13Mwhr by 2035.

The cost of a new gas utility is $6.26/Mwhr now (U.S. Energy Information Administration {EIA} Annual Energy Outlook 2019 AEO2019.....by the way, this reference agrees with Berkel;ey's current cost of wind and solar.) These comparison are all based on a 30 year life span. The story would be a lot different comparing to coal, but we're not building coal plants anymore. Renewables just can't compete with natural gas.

But we have to look beyond that analysis because we're not really talking about expanding our electrical output, we're talking about replacing existing fossil generation with renewables.

What we're doing today is using wind and solar to partially cut back on using the installed fossil generation when wind and solar are available (about 25% of the time for solar and 35% for wind). The $20-$25/ Mwhr cost for the renewables is offset by the reduction in variable cost for fossil which is about $2/Mwhr for gas and $4/Mwhr for coal. The capital cost for fossil is already sunk cost so we can't save that cost. It's costing us the difference of $20-25 minus $2-4 to reduce CO2 emmisions.

The Berkeley Report is going a step further and actually replacing 90% of the fossil plants by shutting them down. They recognize that shutting down most of the fossil results in a need for battery storage, which we avoid with the current "cherry picking" strategy. This is even more expensive than our current strategy. How much is a little vague; they don't breakout the cost of storage.

I won't even go into the lost opportunity cost resulting from the diversion of resources into such a program. I'll assume we could find the resources and we could live with the reduction in our standard of living. But we have to get over this idea that requiring more manpower to get the same output is a good thing. The logic that this program is good because of more jobs is like saying we should go back to building highways with picks and shovels even though it would cost an order of magnitude more.

So to get rid of fossil will take a major up front investment. The cost savings from reducing CO2 are well down the road. I doubt you could find a climate scientist to agree we would see any effect this century. But what we do now will help in the centuries to come. CO2/temperature is such a slow, long term issue I wonder if cutting back fossil to 90% in 15 years is any significant advantage over doing it in 30 years as the old fossil plants are retired.

BaerbelW at 01:45 AM on 9 October 2020

Critical Thinking about Climate - a video series by John Cook

Update: Part 7 - 23 ways to mislead (41 minutes) added to the list. Happy watching!

RedBaron at 00:00 AM on 9 October 2020

Getting involved with Climate Science via crowdfunding and crowdsourcing

What is the rate a new regenerative agricultural method sequesters carbon in the soil?

34% funded and 20 days left. Thanks so much for those who helped!

wilddouglascounty at 23:55 PM on 8 October 2020

What Tucker Carlson gets wrong about causes of wildfires in U.S. West

Daniel B,

What your very impressive statistics points out is that the window for safe controlled burns has shrunk and in some years has disappeared altogether. This has occurred in other parts of the country as well. But that doesn't mean that safe controlled burns should be abandoned as a management tool since fire is a central component of most terrestrial ecosystems. In fact, it makes the increased risk of catastrophic scale fires due to aridification makes controlled burns even more important than ever because of the alternatives. A wildfire season in Kansas in 2016 burned over 400,000 acres of mostly grassland that was being invaded by woody species such as highly flammable eastern red cedar, Juniperus virginiana. Had controlled burns been used in those areas during wetter years to control the fuel supply, the damage would have been far less, and as folks found out in following years, the pastures were greatly improved by the removable of the woody invasives. So the trick is to adapt the controlled burn regimen to actively seek out the shrinking windows of opportunity that climate change has created.

michael sweet at 21:35 PM on 8 October 2020

Berkeley study: 90% carbon-free electricity achievable by 2035

Doug Cannon,

Did you watch the video? They clearly state that renewable energy will be easy to install because it is cheaper than fossil fuels. Your faux concern about debt and $1.7 trillion dollars is simply fossil propaganda. Yes it seems like $1.7 trillion is a lot of money, but it will cost us $2.5 trillion for fossil energy. If you count in the climate and pollution costs fossil fuels cost much, much more than renewable energy.

You are like a teenager who tells their parent "This Toyota Camery costs $20,000. That is way to expensive. We will have to buy the Ferrari instead".

You cannot examine just the cost of renewable energy. You must compare the cost of renewable energy to fossil energy. Renewable energy will be installed by utilities because it is cheaper to build a new renewable energy plant and pay the mortgage than it is to run a fossil fuel plant with no mortgage. The coal, oil and gas cost money while sun and wind are free. In addition, after 2035 the now mortgage free renewable energy plants will continue to generate power using free sun and wind so prices in the long term will go down even more. And renewable energy creates more jobs.

Eclectic at 10:08 AM on 8 October 2020

Critical Thinking about Climate - a video series by John Cook

Nigelj, in general you are correct about "sceptics" revising their previous position ~ when finally all the world and his wife are pointing the finger of scorn & reproach.

That would be so for the milder cases of climate denialism, over the next 20 years, I expect. But not so much for the hard-core denialists (you know the type) . . . they use a seemingly-infinite amount of motivated reasoning to resist the reality which is staring them in the face.

For the hard-core cases, the "noisiness" of data over the coming decades ~ will be a hook for their every hope. Every pause/hiatus in surface temperature, every brief uptick in arctic sea-ice extent, every season which happens to be rather quieter in hurricanes / wildfires / sea-level-rise . . . every example will be pointed to as a fore-runner of the coming Cooling Century which will confound the mainstream scientists.

These cases are the hard-core denialists who will maintain their position . . . right up until they themselves fall to the final sweep of the Reaper's Scythe.

nigelj at 06:33 AM on 8 October 2020

Critical Thinking about Climate - a video series by John Cook

Then when ultimately proven wrong by events, I've noticed sceptics either 1) claim they were never warned clearly enough about the problem, or 2) they believed all along and were just expressing some harmless scepticism to be balanced. Outrageous and despicable of course. People will go to huge lengths to avoid admitting they are wrong.

Eclectic at 21:11 PM on 7 October 2020

Critical Thinking about Climate - a video series by John Cook

The "skeptics" - those who are in denial about climate science - are like gambling addicts.

Intellectually the gambling addict knows that he is not going to win in the end, because elementary mathematics show that the House is destined to win. But emotionally, the addict is strongly drawn to bet against the House, and he is always hopeful that somehow magically he will come out as victor.

As time progresses, the evidence continually grows that the House is winning. But the addict cannot admit he is wrong. The addict keeps on doubling down.

"It's not happening . . . it's not us . . . the experts disagree . . . it's good for us . . . it is hopeless to transfer to renewable energy." Rinse and repeat. Then use all five arguments at once. Then eventually retreat to full-on Conspiracy. Then double down on everything.

nigelj at 12:50 PM on 7 October 2020

Critical Thinking about Climate - a video series by John Cook

An example of climate change sceptics who give mixed messages might be Roy Spencer, a sceptical leaning climate scientist. He says in his writings that some warming is human caused, but that much of the warming is natural, so he is not in complete denial apparently. Except that he also signed an evangelical declaration on global warming that said "the recent warming is one of many natural cycles through history" (note it didnt say "partly"due to a natural cycle but clearly means its all natural). Refer to his bio on wikipedia. Another sceptic with ever changing views is Judith Currie, depending on her audience.

Doug Cannon at 06:46 AM on 7 October 2020

Berkeley study: 90% carbon-free electricity achievable by 2035

This is a great start towards coming up with a plan rather than just a bumper sticker.

I don't see debt as a problem; that's merely a way to direct resources in the right direction. But the debt has to be borrowed from somewhere and that diverts limited resources to this project. The cost of doing that has to be considered.

We can generate about $4.5trillion in capital each year (production - consumption). That investment generates about 10% return, compounded annually to add to our standard of living. That lost opportrunity cost due to the diversion to this plan has to be evaluated in the overall cost. Where does it come from? investments in health care? infrastructure? reduced consumption?.....

In any case it will have a negative impact on our standard of living. We can afford it, but the people have to undestand the total cost.

It would be good if they included the details of the "$1.7trillion of injected" funds. That seems a little skinny just eyeballing current capital cost. Also the additional 500,000 jobs each year have to come from somewhere. We have to stop looking at reduced productivity as an advantage.

So what is going to incentivise the electric utilities to pick up this ball and run with it. They already have the generating capacity at sunk cost. Their upfront investment is $0 to proceed without this plan. Their best finacial strategy is to proceed as now by building renewable plants slowly and let those plants cherry pick when the sun shines and the wind blows. An order of magnitude cheaper than the 90% clean plan by 2035

nigelj at 06:35 AM on 7 October 2020

Critical Thinking about Climate - a video series by John Cook

JoeZ @3, most climate change sceptics I know of are very dismissive of the whole climate issue. This includes both qualified people and laypeople just expressing an opinion. People who write sceptical books possibly come across as less dismissive of the climate issue, but only because they wont get published if they come across as complete lunatics. Their public utterances are not always consistent with their books.

One Planet Only Forever at 05:08 AM on 7 October 2020

Critical Thinking about Climate - a video series by John Cook

JoeZ, You should have put in the 30 minutes effrot to watch the first video before commenting on it.

Daniel Bailey at 03:35 AM on 7 October 2020

What Tucker Carlson gets wrong about causes of wildfires in U.S. West

JoeZ, increased forest fire activity across the western U.S. in recent decades is due to a number of factors, including a history of fire suppression and human encroachment in forest regions, natural climate variability, and human-caused climate change. Forest management would help in some areas, however the wildfire numbers and burned area are also increasing in non-forest vegetation types. Wildfire activity appears strongly associated with warming temperatures (California spring/summer temperatures have increased by more than 5 degrees Fahrenheit since 1970) and earlier spring snowmelt.

Source: NASA

"For all ecoregions combined, the number of large fires increased at a rate of seven fires per year, while total fire area increased at a rate of 355 km2 per year. Continuing changes in climate, invasive species, and consequences of past fire management, added to the impacts of larger, more frequent fires, will drive further disruptions to fire regimes of the western U.S. and other fire-prone regions of the world."

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GL059576

Since the 1980s, the wildfire season has lengthened across a quarter of the world's vegetated surface.

"We show that fire weather seasons have lengthened across 29.6 million km2 (25.3%) of the Earth’s vegetated surface, resulting in an 18.7% increase in global mean fire weather season length. We also show a doubling (108.1% increase) of global burnable area affected by long fire weather seasons (>1.0 σ above the historical mean) and an increased global frequency of long fire weather seasons across 62.4 million km2 (53.4%) during the second half of the study period."

https://www.nature.com/articles/ncomms8537

"The start of the Southwestern fire season—as indicated by the date of first large-fire discovery—has shifted more than 50 days earlier since the 1970s, accounting for about one-third of the increase in the length of the fire season. The substantially earlier SW fire season start is consistent with warmer temperatures and earlier spring seasons leading to earlier flammability of fuels in SW forests."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4874415/

"Anthropogenic increases in temperature and vapor pressure deficit significantly enhanced fuel aridity across western US forests over the past several decades and, during 2000–2015, contributed to 75% more forested area experiencing high (>1 σ) fire-season fuel aridity and an average of nine additional days per year of high fire potential.

Anthropogenic climate change accounted for ∼55% of observed increases in fuel aridity from 1979 to 2015 across western US forests, highlighting both anthropogenic climate change and natural climate variability as important contributors to increased wildfire potential in recent decades.

We estimate that human-caused climate change contributed to an additional 4.2 million ha of forest fire area during 1984–2015, nearly doubling the forest fire area expected in its absence.

Natural climate variability will continue to alternate between modulating and compounding anthropogenic increases in fuel aridity, but anthropogenic climate change has emerged as a driver of increased forest fire activity and should continue to do so while fuels are not limiting."

https://www.pnas.org/content/113/42/11770

"By 2100, if greenhouse gas emissions continue to rise, one study found that the frequency of extreme wildfires would increase, and the average area burned statewide would increase by 77 percent. In the areas that have the highest fire risk, wildfire insurance is estimated to see costs rise by 18 percent by 2055. "

https://climateassessment.ca.gov/state/overview/#wildfire

"The clearest link between California wildfire and anthropogenic climate change thus far has been via warming-driven increases in atmospheric aridity, which works to dry fuels and promote summer forest fire, particularly in the North Coast and Sierra Nevada regions.

Importantly, the effects of anthropogenic warming on California wildfire thus far have arisen from what may someday be viewed as a relatively small amount of warming. According to climate models, anthropogenic warming since the late 1800s has increased the atmospheric vapor-pressure deficit by approximately 10% and this increase is projected to double by the 2060s. Given the exponential response of California burned area to aridity, the influence of anthropogenic warming on wildfire activity over the next few decades will likely be larger than the observed influence thus far where fuel abundance is not limiting.

Since the early 1970s, California's annual wildfire extent increased fivefold, punctuated by extremely large and destructive wildfires in 2017 and 2018. This trend was mainly due to an eightfold increase in summertime forest‐fire area and was very likely driven by drying of fuels promoted by human‐induced warming. Warming effects were also apparent in the fall by enhancing the odds that fuels are dry when strong fall wind events occur.

The large increase in California’s annual forest-fire area over the past several decades is very likely linked to anthropogenic warming.

Human‐caused warming has already significantly enhanced wildfire activity in California, particularly in the forests of the Sierra Nevada and North Coast, and will likely continue to do so in the coming decades."

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019EF001210

Wildfire mitigation efforts can reduce wildfire intensity and severity while improving forest resilience to fire, insects and drought. The total area burned by wildfires is a trend driven by the warming climate (which is warming because of human activities), so mitigation efforts will not likely be able to affect the total area burned trend.

https://link.springer.com/article/10.1186/s42408-019-0062-8

Droughts in the Southwestern US have been made nearly half-again worse by human activities and are projected to worsen yet.

https://science.sciencemag.org/content/368/6488/314

These droughts couple with rising temperatures, reduced soil moisture and lower humidity to kill vast amounts of trees, providing an ever-increasing amount of fuel loads for wildfires.

https://science.sciencemag.org/content/368/6488/238

California’s frequency of fall days with extreme fire-weather conditions has more than doubled since the 1980s. Continued climate change will further amplify the number of days with extreme fire weather by the end of this century.

https://iopscience.iop.org/article/10.1088/1748-9326/ab83a7

https://twitter.com/CAL_FIRE/status/1311722710284693505

There is strengthened evidence that climate change increases the frequency and/or severity of fire weather around the world. Land management alone cannot explain recent increases in wildfires.

Analysis shows that:

• Well over 100 studies published since 2013 show strong consensus that climate change promotes the weather conditions on which wildfires depend, enhancing their likelihood.

• Natural variability is superimposed on the increasingly warm and dry background conditions resulting from climate change, leading to more extreme fires and more extreme fire seasons.

• Land management can enhance or compound climate-driven changes in wildfire risk, either through fuel reductions or fuel accumulation as unintended by-product of fire suppression. Fire suppression efforts are made more difficult by climate change.

• There is an unequivocal and pervasive role of climate change in increasing the intensity and length in which fire weather occurs; land management is likely to have contributed too, but does not alone account for recent increases in wildfire extent and severity in the western US and in southeast Australia.

Human-induced climate change promotes the conditions on which wildfires depend, enhancing their likelihood and challenging suppression efforts. Although the global area burned by fires each year is declining, the majority of this trend is explained by conversion of natural savannahs and grasslands to agriculture in Africa (Andela et al. 2017). In contrast, the area burned by forest wildfires is increasing in many regions, including in the western US and southeast Australia.

• “Fire weather” refers to periods with a high likelihood of fire due to a combination of high temperatures, low humidity, low rainfall and often high winds.

• Human-induced warming has already led to a global increase in the frequency and severity of fire weather, increasing the risks of wildfire.

• Land management can ameliorate or compound climate-driven changes in wildfire risk.

• Wildfires can have broad impacts for human health and wellbeing and for the natural environment.

US fires:

• Fire weather has become more frequent and intense in western US forests.

• Fire weather is driving more wildfire activity in western US forests.

• Demographic factors alone cannot account for the magnitude of the observed increase in wildfires in the western US, but increased population leads to greater impacts.

• Land management practices are contributing factors, but cannot alone explain the magnitude of the observed increase in wildfires extent in the western US forests in recent decades.

Australia fires:

• The scale of the 2019–2020 bushfires was unprecedented.

• Fuel management through prescribed burns and improved logging practice cannot fully mitigate increased wildfire risk due to climate change.

• Extreme weather and Pyroconvection are projected to increase wildfire risk under future climate change in southeastern Australia.

Scientific evidence that climate change is causing an increase in the frequency and extent of fire weather, contributing to extreme wildfires around the world, continues to mount.

The severe droughts in the USA and Australia are signs that the tropics, and their warm temperatures, are expanding in the wake of climate change, due to the warming of the subtropical ocean.

https://public.wmo.int/en/media/news/climate-change-increases-risk-of-wildfires
https://sciencebrief.org/topics/climate-change-science/wildfires
https://sciencebrief.org/briefs/wildfires
https://news.sciencebrief.org/wildfires-sep2020-update/
PDF here

Climate change will continue to drive temperature rise and more unpredictable rainfall in many parts of the world, meaning that the number of days with “fire weather” – conditions in which fires are likely to burn – is expected to increase in coming decades.

Carbon Brief Wildfire explainer

Bob Loblaw at 00:59 AM on 7 October 2020

Critical Thinking about Climate - a video series by John Cook

JoeZ:

With my 40 years of studyig climatology and watching the public discussion, I disagree that it is an exaggeration. I have watched years of mis-informed "skeptic" behaviour that clearly follows the sequence:

I'ts not happening. (instrumental error, site locations, urban heat island, data fudging accusations, etc.)
It's not us (natural cycles, the sun, El Nino, cosmic rays, recovery from Little Ice Ag/Big Ice Age, CO2 change is not from fossil fuels, etc.)
Experts disagree (there is no consensus, science isn't done by consensus, here is a list of "experts" that disagree, the IPCC is political, the greenhouse effect doesn't exist, there is no such thing as "back radiation", etc.)
It's good for us (saves us from the next glacial cycle, CO2 is plant food, agriculture is better in a warmer climate, cold kills more than heat, etc.)
There is no hope - well, that's the next step in the successive retreat from unsupportable "skeptic" positions.

That you finish your comment with the phrase "your cause" tells me a lot about how you are approaching this issue. My cause is good science, which "skeptics" are frequently lacking in.

JoeZ at 21:33 PM on 6 October 2020

Critical Thinking about Climate - a video series by John Cook

I haven't watched the video series yet- but from the top- "Climate change misinformation is like a bizarro world version of this summarized with five categories: it's not real, it's not us, experts are unreliable, it's not bad, there's no hope."

I think that's an exageraton of how climate change skeptics think. Not yet having drawn any conclusions- out of curiousity, I have read a lot of books and blogs by such skeptics. It seems to me that most do agree there is climate change- that humans have something to do with it- that SOME experts are reliable- that some of it is bad- as for "hope", I doubt that word ever shows up one way or the other in such writing. If I am to take climate scientists seriously, I should think such exagerations of the opposite perspective is not helping your cause.

JoeZ at 21:21 PM on 6 October 2020

What Tucker Carlson gets wrong about causes of wildfires in U.S. West

"Overpeck agrees, saying forested areas could benefit from more controlled fires, but “the job is gigantic” and resources to do it inadequate."

It takes a lot of resources to fight the fires too. A thriving forestry industry in CA would be profitable. Some of those profits would go to controlled burns. We don't hear of huge wild fires in the American southeast, where forestry is a huge industry and controlled burns are routine.

One Planet Only Forever at 08:06 AM on 6 October 2020

Critical Thinking about Climate - a video series by John Cook

I would suggest that discussions arguing that fossil fuels help the poor, like at the end of Part 1, should include the following points:

the real cost of fossil fuel use needs to include all of the externalized costs.
the poorest should be helped, which means only the poorest should get any benefit from the continued use of fossil fuels, and that benefit should be helping them transition to sustainable better ways of living.
rapidly reducing fossil fuel use will reduce the harm done to poorer people in the future generations, which will reduce the help they need ni the future.
fossil fuel use is unsustainable, it is non-renewable, so any perception that continued fossil fuel use helps reduce poverty is unsustainable. Fossil fuel help for the poor can only provide temporary assistance.

One Planet Only Forever at 07:16 AM on 6 October 2020

Critical Thinking about Climate - a video series by John Cook

I have only started to watch the series. But I have a couple of comments about the Arctic Sea Ice graph at 3:45 into Part 1:

The chart appears to be presented 0.5 million sq km lower than it should be. Based on NASA presentation of average September extent (consistent with NSIDC presnetation of daily extents):

the minimum in 1979 should be about 7 million not about 6.5
in 2012 the minimum should be about 3.5 million not less than 3

If possible, the Arctic Sea Ice extent chart should be extended to include 2019 and 2020.

But the presentation

MA Rodger at 03:51 AM on 6 October 2020

The Big Picture (2010 version)

Not worth responding on a more-appropriate thread for a very simple response.

The paper In Schulze-Makuch et al (2020) 'Search for a Planet Better than Earth: Top Contenders for a Superhabitable World' is about finding life so they are considering the ideal world for life, not human life. They consider Earth to be a bit too young, too small (so gravity would be best 50% stronger), too cool and too nitrogen-cloaked and also with a moon too small, all this relative to a planet idea for life.

CowboyMC at 01:57 AM on 6 October 2020

The Big Picture (2010 version)

According to this recent article, "A slightly overall warmer temperature, a mean surface temperature of about 5 degrees Celsius (or about 8 degrees Fahrenheit) greater than Earth, together with the additional moisture, would be also better for life.". So it looks like we need to be warmer. See article here: https://scitechdaily.com/some-planets-may-be-better-for-life-than-earth-researchers-identify-24-superhabitable-exoplanets/

Moderator Response:

[DB] "So it looks like we need to be warmer"

Your comment more properly belongs on the "It's not bad" thread (spoiler: there you will find that negative impacts of global warming on agriculture, health & environment far outweigh any positives; please read the post and the multiple versions of it, plus the comments on it before placing any additional comments there).

Participants, any responses to this should be placed there, with a redirect stub placed here.

nigelj at 17:38 PM on 5 October 2020

Interactive: What is the climate impact of eating meat and dairy?

MAR @13, I've now read 152 onwards, and yes I'm not entirely happy signing up to Slartys maths, because the loss of carbon from deforestation and degraded soil sinks could go to several places, its not proven which, although I think its likely some would end up in the atmosphere.

Fwiw, I do think a low meat diet makes sense. RB is probably right that you can get grazing land soils to sequester more carbon, but that will take time to scale up globally, so eating less meat is a practical thing that is immediately possible.

MA Rodger at 15:31 PM on 5 October 2020

Interactive: What is the climate impact of eating meat and dairy?

nigelj @10,

While Slarty Bartfast has not fully set out what he is saying, he is apparently still signed up to the description he set out on the 'breathing contribution' thread @152 & 155. On the strength of your comment @10, Slarty Bartfast @11 tries to also sign you up to it, saying your comment @10 is "exactly what I am arguing."

If you examine what is set out on that other thread, Slarty Bartfash appears to be saying that the CO2 emissions from a reservoir of carbon within the carbon cycle will be fixed by the nature of that reservoir. The reservoirs are listed as Soils, Plants, Animals, Atmosphere, Ocean and from the Soils a reservoir of 1,500Gt(C) is emitted 60Gt(C) of CO2 annually, 4% of its volume. From Animals the ratio of emissions-to-reservoir had been calculated as 800% (calculated @152 in that thread). As the reservoir of Animal carbon has increased with burgeoning human population and livestock herds, the Animal reservoir is considered increased, with its increased emissions balanced by an identical reduction in the Soils emissions. To achieve this Soils emissions reduction, which is fixed at 4% of reservoir, the Soils reservoir must shrink by 63Gt(C) while the increase in the Animal reservoir with its emissions 800% of reservoir will only increase by 0.3Gt(C).

"There is only one other place that most of the remaining 62.7 GtC can go: the atmosphere." This then is the origin of Slarty Bartfast's 30ppm atmospheric CO2 increase. I would hazard a guess that is not something you would feel entirely happy signing up to.

Bob Loblaw at 00:32 AM on 5 October 2020

Interactive: What is the climate impact of eating meat and dairy?

nigelj:

Where Slarty gets things wrong is in assuming that there is some "steady state" or "equilibrium" that has been remaining constant prior to recent human activity.

For example, in comment #7, he states "In effect they divert carbon directly into the atmosphere that would otherwise have first entered the soil and then decomposed." Decomposition also releases carbon to the atmosphere. In some ecosystems this decomposition is extremely rapid; in others somewhat slower. Many different parts of the carbon cycle act at different rates, and those rates all vary over time - so carbon stores vary over time.

I am most faimliar with the carbon budget of the boreal forest. Boreal forests have cycles of growth, cycles of fire, cycles of decomposition, cycles of changes in fluxes and stores. This happens naturally. Dynamics are affected by human activities such as harvesting and forest management - but this is not some alteration from a mythical "steady state" where "nothing changes".

All carbon stores and fluxes are dynamic. Slarty's post #7 also contains the phrase "Their reasoning was based on the carbon cycle: what goes in must come out. So nothing can change, except that it does."

His position that our understanding of the carbon cycle implies "nothing can change" is a strawman. He clearly does not understand the carbon cycle - how it works in reality, how it is modelled.

CD at 08:27 AM on 4 October 2020

Interactive: What is the climate impact of eating meat and dairy?

@10 nigelj

You are correct. That is exactly what I am arguing. But I am also arguing that the actual percentage change in the carbon sinks due to "the big explosion in numbers of cattle and humans since 1900" is still relatively small when compared to the impact of fossil fuels.

I am also arguing that the two contributions are fundamentally different. If future carbon emissions from cattle and humans were to remain constant over time, then there will be no change in the carbon sinks. That means no future increase in atmospheric CO2 or methane levels. However, if fossil fuel emissions remain constant at current levels, then there will still be a continual increase in atmospheric CO2 levels over time.

That is why I say you cannot equate the two.

nigelj at 06:37 AM on 4 October 2020

Interactive: What is the climate impact of eating meat and dairy?

I think slarty is saying that normally breathing and cattle releasing methane are carbon neutral, but the big explosion in numbers of cattle and humans since 1900 has thrown things out of equilibrium, with the ultimate result of high plant and meat consumption leading to degraded carbon sinks leading to more CO2 released from those sinks into the atmosphere. This looks correct to me. Where is the flaw in his reasoning?

Bob Loblaw at 00:08 AM on 4 October 2020

Interactive: What is the climate impact of eating meat and dairy?

Slarty Bartfast @ 7: "As I pointed out in comment @152 in response to the first article, and also on my own blog (see Post 36), the carbon cycle only applies to the steady state. "

And as was pointed out to you on that thread, you are horribly, completely, absolutely wrong is saying that it only applies to the steady state.

Since you begin with a false assertion, nothing else you say about carbon cycles bears much resemblance to reality.

[Note that Slarty's reference to comment numbers above are on a different thread; Slarty has included links in his comment.]

MA Rodger at 22:03 PM on 3 October 2020

Interactive: What is the climate impact of eating meat and dairy?

Slarty Bartfast @7,

The main error you make is that 'breathing' concerns "the act or process of taking air into your lungs and releasing it." And it results in carbon being added to the 'release' in the form of CO2. (Of course, pedantically plants and 'lower' animals also breathe but without lungs.) The carbon in this cycle was originally sourced from the atmosphere as CO2. So any concern would be if the pools of carbon stored outside the atmosphere in this carbon cycle CO2_[atmosphere] > C_[biosphere] > CO2_[atmosphere] were to alter, as happens for instance when large forests are chopped down.

Unlike the breathing of us billions of humans, the "breathing" you are considering has a different composition and isn't considered to be 'breathing' as it does not concern the lungs (or the equivalent in plants & 'lower' animals) and often comes out of a different orifice. The situation is certainly not the same, as you may or may not argue (it is difficult to tell what you argue), as the carbon cycle being considered is fundamentally different. CO2_[atmosphere] > C_[biosphere] > CH4_[atmosphere] > CO2_[atmosphere].

CD at 09:50 AM on 3 October 2020

Interactive: What is the climate impact of eating meat and dairy?

About 10 years ago SkepticalScience posted an article entitled “Does breathing [by humans] contribute to CO2 buildup in the atmosphere?”
(see here ) Their answer to the question was "no". Their reasoning was based on the carbon cycle: what goes in must come out. So nothing can change, except that it does.

Now we have another article on the same site that effectively argues the opposite: that breathing from farm animals contributes to global warming. The problem is that both these articles are wrong, at least in part, because they both fail to distinguish between the steady state and systems that are evolving over time.

As I pointed out in comment @152 in response to the first article, and also on my own blog (see Post 36), the carbon cycle only applies to the steady state. By definition climate change implies evolution over time. If the number of cows increases then they will change the distribution of carbon between the different reservoirs (air, plants, soil) until a new equilibrium distribution of carbon is achieved. In effect they divert carbon directly into the atmosphere that would otherwise have first entered the soil and then decomposed. I have estimated that the increase in atmospheric CO2 since 1900 due to the increase in human and livestock populations over the same time period to be (much) less than 30 ppm. That increase in CO2 is not going to end life on Earth. In fact it is less than the current increases we are seeing from fossil fuels every 15 years. Vegan lifestyles are not going to save the planet.

So when examining climate change it is the change in the number of animals and humans that is is crucial, not their actual number. And, since 1900, livestock numbers have increased dramatically, while over the same time period the human population has nearly quadrupled. That is the elephant in the room that no-one will discuss, and no amount of vegan virtue signalling will compensate for that.

The problem with this article, and others like it, is that it seeks to equate emissions from cows with emissions from fossil fuels. That is bad science. Even if animals and cars produce the same amount of CO2 and/or methane, they will not cause the same increase in atmospheric CO2 levels because they are acquiring their carbon input from entirely different sources. One is largely self-sustaining, returning the CO2 from whence it came (the atmosphere), with only slight changes to the balance of carbon in the different reservoirs of the carbon cycle due to its own rate of change; the other continuously adds more new carbon to the carbon cycle, starting with the atmosphere, and so dramatically changes the balance of carbon in the different reservoirs. Eating less meat is no substitute for consuming less fossil fuels.

BaerbelW at 19:25 PM on 2 October 2020

Is Nuclear Energy the Answer?

Please note, that we added an important update to this blog post today. We hope that it clarifies what we are looking for in case somebody would like to write an article about nuclear energy.

BarbNoon1 at 10:56 AM on 2 October 2020

New rebuttal to the myth 'Holistic Management can reverse Climate Change'

Veganic farming should be promoted instead of using animals. It's a simple solution, really. Use a lot of the successful techniques of regenerative farming, but leave out the animals.

https://goveganic.net/article129.html

Keithy at 10:39 AM on 2 October 2020

Interactive: What is the climate impact of eating meat and dairy?

Soil can't save us, nor can sequestration of the coal power plants themselves.

I hate nuclear but it is the only solution for big cities.

Solar and wind are here but the profit motive still needs to be engineered... Electric cars depend on all of this!

Moderator Response:

[PS] Assertions with no supporting evidence are simply sloganeering. Put up evidence to back you what claim.

RedBaron at 23:57 PM on 1 October 2020

Interactive: What is the climate impact of eating meat and dairy?

I have said it before here. The idea we can mitigate global warming with a diet shift alone, and not a change in production methods, is absolutely wrong and most likely impossible with current technology.

The whole idea hatched from the supposed benefit of using grain for ethanol production instead of meat production, then using the ethanol along with as yet undeveloped CCS technology and putting those CO2 emissions far underground in old wells etc. This would give a supposed negative carbon footprint.

There are even a few pilot CCS power plants that managed to put some carbon emissions in the ground this way. But at a huge cost and loss of efficiency as great or greater than any benefit derived.

Solar and wind are far more cost effective and efficient ways to generate energy. And soil sequestration is a far more cost effective and efficient way to sequester carbon.

Once you realise this, then you can easily see that it is not the tomato nor the beef on your plate that determines the carbon footprint of your diet, but rather how that food was produced. Methods that improve soil carbon whether producing vegetable or animal foods will lower your carbon footprint. For this reason it is entirely possible to have a tomato with a significantly larger carbon footprint than a 8 oz steak.... if the tomato was produced on land with degrading soil then shipped 100's of miles and the beef was produced on local land with regenerating soil.

Alan Russell at 10:48 AM on 1 October 2020

Interactive: What is the climate impact of eating meat and dairy?

I'm disappointed to see such misinformation here, I expect better. Imo, anyone using 100-year carbon dioxide equivalent emission factors for methane should probably be ignored, or at least not be published.

Here are some better atricles on a similar subject:

- LINK1;

- LINK2;

- LINK3.

Moderator Response:

[DB] Shortened and activated URL's breaking page formatting.

RedBaron at 07:47 AM on 1 October 2020

Startups aim to pay farmers to bury carbon pollution in soil

Thanks everyone! And yes Doug I did send a note from your contact form. Still waiting a reply. And Eclectic, I really don't have any idea why you are having difficulties.

John Hartz at 00:58 AM on 1 October 2020

How Climate Change is Worsening California's Fires

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