Nota publicada a l’edició digital del diari The Guardian del passat dimarts 31 de desembre, per Dana Nuccitelli.
2013 saw a lot of good climate science and myth debunking, but not much progress in solving the climate problem
As 2013 comes to a close, a review of the key climate events of the year reveals some interesting new research and effective myth debunking, but little net progress in terms of addressing the problem through policies to reduce greenhouse gas emissions.
Beginning with the good news, the myth of the global warming ‘pause’ – which has helped policymakers justify delaying action to address climate change – was thoroughly debunked in 2013. A paper published by Kevin Cowtan and Robert Way showed that, in addition to the myth being a clear case of cherry picking short-term noise in the data, global surface temperatures have actually risen about two and a half times faster over the past 15 years than previously estimated. The short-term ‘pause’ was mostly an artifact resulting from a lack of temperature station coverage in the Arctic, where global warming is happening fastest.
Several other papers this year helped to investigate the cause of the slight slowing in the warming of global surface temperatures. Kosaka & Xie (2013) showed that changes in the Pacific Ocean could account for most of the short-term global surface temperature changes. Along those lines, Watanabe et al. (2013) showed that ocean heat uptake has become more efficient over the past decade, which is consistent with the observations of Balmaseda et al. (2013), who found an unprecedented transfer of heat to the deep oceans over the past decade, consistent with the modeling in Meehl et al (2013).
Putting it all together, we have an increasingly clear picture that while the warming of global surface temperatures has slowed over the past decade, it has not slowed as much as previously thought. The slowed surface warming is due in large part to changes in ocean cycles, particularly in the Pacific Ocean, causing more efficient ocean heat uptake, thus leaving less heat to warm surface temperatures. External factors, like decreased solar and increased volcanic activity, have also played a role in the slowed surface warming, but internal variability due to ocean cycles appears to be the main culprit. In any case, as the 2013 IPCC Fifth Assessment Report showed, the observed global surface warming remains within the range of climate model projections.
In addition to the Cowtan & Way paper, my colleagues at Skeptical Science and I also published several high-impact papers this year, starting with the Cook et al. (2013) consensus paper, co-authored by nine Skeptical Science volunteers. The paper showed that there is a 97% consensus in the peer-reviewed climate science literature that humans are causing global warming. The paper has already been cited in a broad range of scholarly journals and made a big splash in the media, even being the subject of two presidential Tweets. It was also the 11th-most talked about academic paper in 2013.
A study published by myself and John Abraham along with two other colleagues debunked a paper by Syun-Ichi Akasofu that tried to blame global warming on a magical ‘natural recovery’ from the Little Ice Age. As our paper showed, climate changes must be caused by physical mechanisms, and Akasofu’s argument lacked any physical basis. John Abraham also brought together nearly 30 of the world’s top oceanographers to publish an impressive paper detailing the knowns and unknowns about global warming and the oceans. A paper by another of my colleagues, Richardson (2013) demonstrated that the modern increase in atmospheric carbon dioxide is entirely human-caused, debunking a contrarian paper that wrongly claimed otherwise.
An important paper by Marcott et al. (2013) also showed that the warming we’ve witnessed in the last 100 years is unlike anything that happened in the previous 11,000+ years. Taking their results into account, the warming yet to come in a business-as-usual scenario looks downright scary. A brand new study by Sherwood et al. (2013) tackles the question of how cloud cover will change and interact with global warming as the climate continues to change. The cloud feedback question is one of the largest remaining uncertainties in future climate predictions, so this is an important new paper. Unfortunately it finds that clouds will act to amplify global warming, suggesting that the planet will warm at least 3°C in response to a doubling of atmospheric carbon dioxide, which also suggests at least 4°C global surface warming by 2100 if we continue with business as usual policies.
With regards to those policies, 2013 was a bit of a mixed bag. Australia elected a majority government that has pledged to eliminate its carbon tax. In Canada, the government has paid lip service to climate change while muzzling its scientists and doing everything possible to increase its emissions through maximum development of the tar sands. However, on a local level, British Columbia’s revenue-neutral carbon tax remains highly popular and successful, and California implemented a similarly popular carbon cap and trade system in 2013. And the national news isn’t all bad, as the US government has issued draft regulations on greenhouse gas emissions from new power plants, and is working on regulations for existing power plants. There are also encouraging signs that China is beginning to address its rapid emissions growth. However, on an international level, 2013 passed with very little progress in terms of establishing a new international climate agreement. 2015 is the target date for new emissions reductions plans.
Overall, 2013 was a productive year in terms of reducing the consensus gap and debunking the ‘pause’ myth. Climate policies were a mixed bag, with some steps backwards and some steps forward. Climate media coverage was likewise a mixed bag, with continued false balance and inaccurate reporting from the politically conservative media, also seeping into the BBC. The New York Times eliminated its environment desk, but The Guardian stepped in to fill the gap with its new Environment Blogs.
A lot of interesting new climate research was published during the year, including a new IPCC synthesis report. However, progress toward solving the climate problem remained far too slow. Here’s to 2014 being a more productive year for climate solutions.