However, the lead author (Andrew MacDougall) of the recent paper that estimated the ZEC has used one of the models to try and assess the effect of the permafrost carbon feedback on the zero emissions commitment. They carried out a perturbed parameter experiment (i.e., run the same model many times, but vary the parameters), and considered scenarios where 1000 PgC is emitted before emissions go to zero, and another where 2000 PgC is emitted (for context, total emissions to date is about 600 PgC).
There were quite a lot of details that I won’t go into, but the main result is presented in the above figure, which shows how permafrost infuences the ZEC in the 1000 PgC runs (left-hand panel) and 2000 PgC runs (right-hand panel). In other words, how much extra warming is there after emissions go to zero when compared to equivalent runs that don’t consider permafrost.
The basic result (see Table below) is that on multi-decade timescales, the effect is small (probably less than 0.1oC) but that it will increase with time, possibly adding a few tenths of a oC after 500 years. For reference, the temperature increase in the 1000 PgC run when emissions go to zero is about 1.5oC, so after a few hundred years we could have warmed by ~2oC. This isn’t great, but this additional warming would be relatively slow and it’s still considerably smaller than the baseline warming (i.e., most of the warming we’re likely to experience is due to our emissions, not due to these feedbacks).
The analysis also suggests that the impact doesn’t depend strongly on cumulative emissions; the effect is similar for the 1000 PgC and 2000 PgC runs. This is mostly because the linear relationship between emissions and warming breaks down in these models when cumulative emissions are high. There are, however, indications that this may not be a robust results and, hence, it is possible that the effect will continue to increase with increasing emissions.
Also, even this study doesn’t consider abrupt thaw, which could accelerate permafrost processes over the next few centuries. This could further increase the permafrost, but probably by 10s of percent. This probably won’t change the basic result. The effect of permafrost on the zero emission commitment (ZEC) is probably small on multi-decade timescales. Hence, this doesn’t change that the ZEC is probably close to zero on these timescales.
On longer timescales (centuries) the effect of permafrost will probably increase, but is probably still going to be much smaller than the warming due to direct anthropogenic emissions. It could increase warming from 1.5oC to ~2oC over a period of a few centuries, but it seems unlikely that it will commit us to much more than 2oC if we are able to get emissions to zero well before we cross that warming threshold. This isn’t necessarily great news, but it still indicates that the dominant factor in determining how much we will warm is how much we end up emitting.
SearchScene is a charitable search engine that donates a big-hearted 95% of its profits to charity, focusing on charities that help fight climate change and alleviate the suffering caused by climate change.
SearchScene’s elevator speech
So I installed it and was impressed by its unobtrusiveness. Willing to know more, I looked at their FAQ, then noticed a Contact page. Took the chance to offer them a Q&A for my We Are Science series. (Note the first question.) Neil responded that he was following AT on teh tweeter, and so accepted. Here they are:
Q1. I read that Neil worked on Cryosat and Ciara was a communication consultant for Harvard and MIT. Could you (Neil and Ciara) describe what you were doing exactly?
Neil: I was working on the simulator for the Cryosat spacecraft – specifically the AOCS (Attitude and Orbit Control System) part of it. The simulator is a computational model of the spacecraft that the European Space Agency use to test failure scenarios and to help train the flight control team for launch and early operations. Cryosat failed to make orbit back in 2005 due to a launch vehicle malfunction, which resulted in the total loss of the spacecraft. Soon after this, I left the space industry and started an internet business.
Ciara: From 2007 to 2009, I worked as Science Communication Consultant for the Massachusetts Institute of Technology (MIT), and then Harvard University in the USA, on an innovative science education project called Picturing to Learn. The project was run by award-winning science photographer, Felice Frankel, whose work has appeared on the cover of Nature on numerous occasions. Felice Frankel’s idea was that one of the best ways to understand a concept is to try and explain it to someone else in simple terms, often through the use of visual imagery. I helped the PtL team create a methodology and database for analysing their students’ science communication drawings (and their experience of doing the work). The drawings often relied on visual analogies in chemistry, biology, and physics (my particular area of expertise). It is important to know the limitations of any scientific analogy because, while they have great power to clarify and communicate complex concepts, they may also be misleading, especially for students. One of the striking things to emerge from the PtL project was how drawings can be a great way of identifying misconceptions which students have about a scientific concept. The educator can then pay particular attention to those areas where students have those common misconceptions, and try and correct them. Our PtL team also ran some collaborative workshops where science students collaborated with visual design students to explain such things as why the sky is blue. The science students needed to explain the concepts to visual design students, who did not have a scientific background, and the visual design students needed to find ways to render those concepts in a visually engaging way, without generating misconceptions. In the process, both parties learned a great deal from each other.
Q2. When or how did you get the idea of doing something about AGW (Anthropogenic Global Warming)?
The climate crisis is the burning issue of our time. We are the first generation to truly appreciate its consequences and the last that can do something meaningful about it. After our daughter was born 4 years ago, we started worrying about the sort of world that she would grow up in. We also saw huge corporations, like Google, raking in billions of dollars and just sitting on huge stockpiles of cash – cash that could be used to make a huge positive difference in the world. We tried various charitable search engines instead, but we were disappointed by the search experience. We thought we could do better, so we created SearchScene.
Despite the fact that SearchScene is a great alternative search engine, we have found it challenging (and very expensive) to get the word out about it. So it would be great if your readers could try SearchScene and, assuming that they like it, to share it with their family, friends and work colleagues.
Q3. The search results in Search Scene seem similar to what I can find with other more dominant search engines. But it feels like the good ol’ days of search engines. Am I escaping my filter bubble?
You are indeed escaping your filter bubble. We don’t store your searches or your IP address or profile you in any way. Our search results are specific to your country, but that’s about it. They are independent of any previous searches you’ve made. This is a level of privacy that you just don’t get on Google.
Q4. Where does the name come from?
We show you different scenic wallpaper backgrounds on our homepage that change each time you refresh the page, hence the name SearchScene. It’s worth noting that you can switch these off if you like and revert to a blank, Google-like, minimalist homepage. You can also set your own wallpaper image from your computer or mobile device.
Q5. I experienced SearchScene a few weeks already, and my experience with it has been positive. (Reached 1,226 tokens this evening.) The landing page is sexy without being clunky. How did you make it so responsive?
Congrats on reaching 1,226 tokens! Hope you can stick with it! The homepage loads fast because we cache the next wallpaper image on your device. So when you refresh the homepage, it’s already downloaded the wallpaper image in advance. We use a content delivery network to further speed up the load times. Additionally, our search results are served up from servers in the UK and in the US and we maximise caching to achieve the fastest possible load times.
Q6. I like your selection of charities, but they are quite generic. I was wondering if you have considered looking into stoves and solar light. The two seem (at least to me) extremely important issues surrounding climate change and energy poverty:
(The two links are only for illustration purposes. There are many others. I found them back using Search Scene, of course!)
Generic is what we were aiming for with the charities. We have traffic from all over the world – mainly the UK, US and Canada – and we wanted international charities that people have heard of and that people trust.
As far as our impact metrics are concerned, these are just representative of how these charities might spend our donations. Eden Reforestation Projects obviously use our donations to plant trees – that’s what they do. However, our other supported charities support many causes, so although we state that UNHCR provide malaria treatments, this is just an example impact metric we chose. They might just as easily spend that money on solar lamps or burn stoves, etc. We don’t dictate to charities how they should spend our donations – we let them spend it as they see fit. In choosing impact metrics, wherever possible we tried to go for things that would create an emotional response in our users. Who can argue that curing someone of malaria is not money well-spent? We also went for metrics that would scale up quickly. Some charities offer more meaningful metrics than others.
Q7. I noticed there’s a browser in a phone store. What’s your next big thing?
We have Firefox-based browser apps in the Google Play store (for Android) and in Apple’s App Store (for iPhones and iPads). The next big thing really depends on whether people are willing to use and share SearchScene. If we can scale up our traffic, and get a long-term partnership with Microsoft Bing, we would ideally like to increase our privacy features and eventually take on DuckDuckGo. After all, what’s better than a private search engine? A private search engine that donates nearly all of its money to big charities, helping to make a difference in the world! Ideally, we would like SearchScene to become the natural ethical alternative to Google.
Q8. The last question is always about music. What are you listening to these days? Shoot me a video or two!
The results are nicely explained at the beginning of the paper. When considering agricultural emission scenarios from 2020-2040:
A sustained ~0.35% annual decline is sufficient to stop further increases in global temperatures due to agricultural CH4 emissions. This is analogous to the impact of net-zero CO2 emissions.
A ~5% annual decline could neutralize the additional warming caused by agricultural CH4 since the 1980s.
Faster reductions of CH4 emissions have an analogous impact to removing CO2 from the atmosphere.
What this illustrates is that fairly modest reductions in agricultural methane emissions (~0.35% per year) can largely stop future agricultural methane-driven warming, stronger methane emission reductions (~5% per year) can reverse the agricultural methane-driven warming since about 1980, and even faster reductions would be analagous to negative CO2 emissions.
The reason these results might seem at odds with previous estimates is that GWP* better estimates methane-driven warming than GWP100, or GWP20.
However, even though modest methane emission reductions can have a big impact on future methane-driven warming, the paper also points out that
a 1.5% annual increase in CH4 emissions would lead to climate impacts about 40% greater than indicated by GWP100.
In other words, if methane emissions continue to increase, then they will lead to substantial future warming, which the standard metrics may under-estimate (GWP100, at least).
Also, even though this indicates that modest reductions in methane emissions can have a substantial impact, the remaining carbon budget for 1.5C is small enough that if we really do want a good chance of limiting warming to 1.5C, then we’d probably still need to make substantial cuts to methane emissions, along with rapidly reducing CO2 emissions. However, I do still think it’s worth pointing out that even modest reductions in methane emissions can have a big impact on future methane-driven warming.
For example, it says we’re facing tipping points which could trigger runaway warming, which is simply wrong. A true runaway is essentially impossible in our current climate state. The albedo is too high and the sun is too faint. We could trigger some feedbacks that would amplify the warming, and these are expected to become more significant the more we warm. However, if we start to reduce emissions soon and get to (net) zero by around mid-century, then – although these may still be important – they may not be all that significant. I wrote a post a while ago that tried to explain the difference between feedbacks, runaway, and tipping points.
The article then goes on to say
Even rapidly accelerating the end of fossil fuel burning will not slow warming in a timeframe relevant to this threat……….
To slow warming we must keep our focus on cutting CO2 but now also focus intensely on the shorter lived, far more potent gases such as methane.
The science explains this. Whereas CO2 drives warming slowly over a century, methane drives warming quickly – in around a decade.
I agree that we should keep our focus on CO2 and also focus on the shorter-lived species, such as methane. However, the claim that CO2drives warming slowly over a century is wrong. Peak warming from a pulse of CO2 actually occurs after about a decade. Hence, reductions in CO2 emissions will occur on a similar timescale. Hence, we should be careful of thinking that dealing with short-term warming requires a more intense focus on methane, rather than on CO2.
The article then goes on to suggest that the warming potential of methane over a period of 10 years is 90-115 times that of CO2. What this is referring to is the global warming potential (GWP) and it is indeed the case that this is much greater for methane than for CO2. However, it doesn’t quite mean what the article implies.
How much warming we get from methane emissions depends on how they’ve been changing. If emissions are going up, then this will result in warming. However, if they’re constant there should be little additional warming. If they’re going down, then some past warming will actually be reversed. So, methane does indeed have a much higher GWP than CO2 over a timescale of decades, but this doesn’t necessarily mean that methane emissions will drive much more warming than CO2 emissions. If you want to understand why this is, I tried to explain it in this post, and this Carbon Brief article by Michelle Cain is also very good.
Essentially, as long as we are emitting CO2 there will be CO2-driven warming, which will only stop (but not reverse) when CO2 emissions go to zero. Warming due to methane, on the other hand, will mostly stop if we get methane emissions to stabilise, and will reverse if we get methane emissions to go down. Given the differences between methane-driven, and CO2-driven warming, how much we will eventually warm depends mostly on how much CO2 we end up emitting.
Of course, this doesn’t mean that we shouldn’t worry about methane emissions. According to the latest IPCC report, methane accounts for a reasonable fraction of the warming we’ve experienced and, since methane emissions are still increasing, will contribute substantially to future warming. If we want to meet the Paris targets, then we will need to deal with both methane and CO2 emissions, especially if we don’t want any overshoot.
However, we do need to be careful of thinking that limiting short-term warming means focussing on methane. As pointed out in this Realclimate post, the long atmospheric lifetime of CO2 means that any delays to CO2 emission reductions are likely to commit future generations to warming that is difficult to reverse and could have been avoided. Methane’s short atmospheric lifetime means that delays to methane emission reductions don’t carry the same risk.
This doesn’t mean, though, that near-term methane emission reductions aren’t important (they are if we want to meet current targets without temperature overshoots). The main point is to be careful of thinking that focussing on methane now can buy us time (it doesn’t) or that it’s now essentially become a methane emergency (it hasn’t).
Mallen Baker is a commentator who runs a youtube channel called Dangerously Reasonable. He tackles contentious issues and tries to assess the various lines of evidence that may, or may not, support what someone is promoting. For example, Mallen did an interesting assessment recently of Bjorn Lomborg’s arguments in which he quoted some of my comments.
He also has guests and asked me if I would like to chat about science communication, with some focus on climate change and whether or not we can still have civil discussions about these kind of topics.
We recorded it last week, and it was posted last night. If you’re interested, the video is below. I don’t do this very often (at all, really) so I felt like I rambled a bit and wasn’t quite as coherent as I might have hoped. As with most people, I also cringe when I see/hear myself on a video.
The site has been a little quiet, but since this blog has been going long enough to have commented on the release of the IPCC AR5 WG1 report, it only seems right to comment on the release of the IPCC’s AR6 WG1 report. In case anyone doesn’t know, the IPCC is the Intergovernmental Panel on Climate Change, AR6 is the sixth Assessment Report, and WG1 is Working Group 1, the Physical Science Basis.
I haven’t read much of the main report, but have read through the Summary for Policy Makers (SPM). The bottom line is that the big picture hasn’t really changed; it’s real, it’s us, there’s strong agreement amongst relevant experts, the impacts could be really severe, we can still do things to limit the impact.
However, I thought I would highlight some of the things that caught my eye, and maybe others can provide other explains in the comments. One of the key highlights in AR5 was that it was extremely likely that most of the observed warming was anthropogenic, and that hasn’t changed: The likely range of total human-caused global surface temperature increase from 1850–1900 to 2010–2019 is 0.8°C to 1.3°C, with a best estimate of 1.07°C (i.e., it’s probably all human-caused).
What does seem to have changed is there seem to be stronger statements about extreme events, in particular heatwaves and extreme precipitation, but also droughts, flooding and tropical cyclones. For example, there is a pretty clear statement that climate change [is] already affecting every inhabited region across the globe with human influence contributing to many observed changes in weather and climate extremes.
The AR6 report also presented a narrower likely range for equilibrium climate sensitivity (2.5oC to 4.5oC) and – unlike AR5 – presents a best estimate of 3oC. It also presents a slightly narrower range for the Transient Climate Response to Cumulative Emissions (TCRE) of 0.27oC to 0.63oC per 1000 GtCO2, with a best estimate of 0.45oC (or 1.65oC per 1000 GtC).
There also seem to be stronger statements about many of the changes, and the current state, being unprecedented over many centuries to, potentially, thousands of years. The report now specifically states that it is more likely than not that no multi-centennial period after the Last Interglacial (roughly 125,000 years ago) was warmer globally than the most recent decade.
There’s plenty more that I could highlight, but overall it seems to be mostly strengthening the basic understanding that we’ve had for quite some time now. Maybe we’ll see less of the “climate change isn’t influence extreme events” narrative that some like to promote, but I wouldn’t bank on it.
If you want to read some other takeaways from AR6 WG1, Realclimate has a new post. As I said above, maybe others could highlight their takeaways in the comments and, if interested, make any others points they might like to make.
Bill McGuire, who is Professor Emeritus of Geophysical & Climate Hazards at UCL, has written a post suggesting that climate scientists should speak out more and that they should
Come down off the fence and choose the path you know, in your heart of hearts, is the right one.
I must admit that when I started publicly discussing climate change – more than 8 years ago – I was a little surprised that more climate scientists weren’t speaking out. However, I think there are a number of reasons why this might be, many of which are quite reasonable.
I think scientists are naturally cautious about what they say publicly. The tendency is to say things for which there is substantial evidence and to avoid speculating about things that are very uncertain. There is also a tendency to avoid saying things that might sound like advocacy, especially when engaging in what might be regarded as reasonably formal science communication.
I do, though, agree with Bill McGuire that there is pressure to not sound alarmist. A consequence of this has been a tendency to focus on what is regarded as likely and to avoid talking about possible worst case scenarios. Again, this can be reasonable, but does run the risk of not making clear that things could end up much worse than what we regard as likely.
However, there is an additional complication. In a simple sense, the outcome depends on two somewhat independent factors: how much we end up emitting, and how sensitive the climate is to the resulting radiative perturbation. So, when considering worst case scenarios, are they worst case in the sense that the climate turns out to be very sensitive, or is it that we continue to increase our emissions, so that a worst case emerges even if climate sensitivity is not on the high end. Of course, the ultimate worst case would be that we continue to increase our emissions and climate sensitivity turns out to be high.
This does make science communication quite tricky, since we can still do things to limit how much we emit and, consequently, to avoid ultimate worst case scenarios. Consequently, there’s a balance between highlighting how bad things could get while also making clear that it’s still not too late to avoid some of the most severe outcomes. However, we also have the complication that even if we do limit our emissions, we could still experience impacts that are more severe than expected (e.g., the recent heatwaves and flooding).
So, I do think this is a pretty complex science communication environment and, in general, I think climate scientists have communicated very effectively (global governments have agreed to take action, even if they haven’t actually done much yet). I do think it would be good if more climate scientists were to speak out. However, I also think we have to be careful of generating a narrative that suggests that the problem is that climate scientists haven’t spoken out enough, rather than it being that others have mostly ignored what is being said.
At the risk of sounding rather arrogant, I find myself getting more and more frustrated by people justifying their position on the basis of a flawed understanding of the scientific evidence. One that seems particularly prevalent at the moment is the idea that cuts in CO2 emissions will have no effect for many decades. This has been used to argue that we should focus on developing resilience, and that reducing methane emissions is important if we want to stabilise the climate faster.
There are two problems I have with this narrative. Firstly, even if it would take many decades to feel the effects of CO2 emission reductions, that doesn’t mean that we shouldn’t be reducing these emissions now. CO2 accumulates in the atmosphere and how much we eventually warm depends on how much we eventually emit. If we don’t focus on CO2 emissions now, then either we’ll emit more than we otherwise could have (and will have to deal with the additional warming and resulting impacts) or we’ll have to make even more drastic emission cuts in the future. If the impact of these cuts would also not be felt for many decades, why would drastic emissions cuts in the future be more justified than doing so now?
The second problem I have is that it’s not actually correct. Recent work has demonstrated that peak warming from a pulse of CO2 emission occurs after about a decade. In fact, the paper that illustrates this, explicitly discusses the misconception that it would take many decades. So, if peak warming from a pulse of CO2 emission would take about a decade, the impact of emission cuts would also manifest on a similar timescale. In other words, the effects would be felt relatively quickly.
What’s important to recognise is that how much we warm in future depends mostly on how much we emit in the future. Since CO2 accumulates in the atmosphere, limiting how much we eventually warm depends primarily on limiting how much CO2 we emit. This doesn’t mean that we should not also focus on developing resilience and also aim to reduce emissions of short-lived greenhouse gases (like methane). However, we shouldn’t do so because we think CO2 emission cuts will have no short-term impact. Not only does this ignore that ultimately we need to limit the total amount of CO2 that we emit, it’s also wrong.
This June we celebrate the tenth anniversary of the best audit ever, a series of posts written by John Nielsen-Gammon, Texas State climatologist. I call him NG because that’s how he signs his comments. The series starts with this entry on his Climate Abyss blog:
The Houston Chronicle revamped its website many times over the years. Each iteration made finding the series harder. So I compiled a list, with each entry archived:
Here’s what I like about the series. It shows how contrarians click: we’re on a quest to experience something nobody’s ever experienced before. It shows how a meteorologist thinks in situ. It also shows how business ventures rest both on trust and distrust, and how life can be fun even when nothing happens. And then there’s this gem:
I think it likely that the eventual impact will be so severe as to reflect disgracefully upon the human race.
NG’s take on the AGW predicament
I took the opportunity to email John, asking him a few questions. He responded:
Q1. How’s life beyond Climateball?
We recently won the contract for the Southern Regional Climate Center, so I’m busy spinning that up. It’s basically a state climate office on steroids, with actually enough external funding to be able to do a decent job. We finished our first actual set of (very limited) climate change projections for Texas, based mostly on observed trends since people around here seem to trust those more:
I’ve pulled back from online and email climate change debates, since I have more than enough climate services work to do without also talking about climate change to people who are just asserting or defending a position.
Q2.If you are still Texas State Climatologist or still meet farming and business folks, do you feel that AGW is something they consider more nowadays?
After Harvey and Uri, I think people are tired of abstract discussions about whether climate change is real and have mostly moved on to actually doing something about all the bad weather. Mitigation is still a political hot potato, but adaptation is something just about everyone can agree on, so that’s where the progress is being made. People are open to the possibility of many types of extreme weather being worse in the future than in the present (climate science says: Harvey yes, Uri no) as long as trends in extreme weather don’t threaten their political identities.
Q3. Any new project (or audit) you’d like to share with climate-oriented readers?
We did some work for the Harris County Flood Control District (HCFCD) recently on extreme rainfall. In addition to concerns about climate change, they wondered whether the official updated analysis of extreme rainfall probabilities had been unduly skewed by Harvey and other recent flooding events in the area. I found that ordinarily they should be concerned about climate change, but the recent spate of extreme rainfall had affected the analysis so much that present-day risk for, say, 100-year rainfall amounts, was probably overestimated. With climate change, the actual risk will probably allow reality to catch up with the overestimates by sometime around the middle of this century. That’s good news for HCFCD, but bad news for just about everyone else, whose risk of present-day extreme rainfall is already underestimated, let alone future risk.
Q4. Any music suggestions? Anything you like would do, with a link to a video. You could tell the readers about the music you listened to most to go through our current plague.
Over the past year, I’ve focused pretty heavily on the Dave Matthews Band channel on Sirius XM. I’m probably getting near to the end of that fetish, as I’ve started hearing DMB music spontaneously in my head. My favorite song of theirs used to be Grey Street — I love the way the refrain expands with each repeat and how the drums nearly explode at the end. But now I think I like Crush most of all, with its sense of wonder and excitement
Plus it’s a good teaching aid for when I want to get students started with the Coriolis Force.
Given that I’ve been writing a blog about climate for a good number of years, I clearly think this is an important topic and am generally supportive of attempts to make it more prominent. So, this group could make an important contribution.
However, I also think there are some reasons to be concerned. Although things have improved over the last few years, this is still a pretty complex communication environment. It can be easy to slip up, say something that’s easily criticised, and undermine what you’re tryng to do. There are lots of people who’ve been engaging publicly in this topic for a long time, some of whom I hope they include, or at least spend some time talking to.
Then there’s the make-up of the group. Those named so far seem reasonably sensible, but there are some prominent people who may not be good additions. So, it will be interesting to see who makes up the rest of the group.
Also, what will the focus be? I’m a scientist, so I do think it’s important to stress our scientific understanding, but science alone does not tell us how to deal with this issue, and convincing people of the significance of this issue involves more than just explaining the science. If, as the news article indicates, the remit will be to press for more urgency, how will they do this in a way that’s effective?
“I’ve been amazed by the response to Independent Sage,” King said. “All 12 members have become media personalities. I hope we get the same level of interest for the climate group.”
Clearly, if you want your message to be heard, you do need to get media exposure. However, there is a difference between finding ways to get your message heard, and aiming to become a media personality. Becoming a media personality is probably pretty easy. Doing so while still remaining credible is probably less so (I will say, though, that I do think those on Independent SAGE who have become quite prominent in the media have generally done well.)
As usual, this has got too long, so I’ll stop here. I think this is an interesting idea and could make a positive contribution. However, this is not the first time that people have been trying to press for more urgency. I hope this group doesn’t think that they can simply step up and easily do what many others have tried before.