Everybody noticed when Barach Obama mentioned the need to address climate change in his Inauguration Address last Monday (21st January). Many became more hopeful; in my case the extra optimism did not last very long. The challenge of climate change has been getting bigger year by year, and several items in the scientific literature this month revealed just how much bigger this problem has become. Items in the media revealed just how politically difficult solving this problem has become, while also showing just how much our climate is changing.
First some climate facts. 2012 was the tenth warmest year on record globally, and the warmest on record in North America. It was about average in precipitation, but that rain did not necessarily fall where and when it used to. Arctic sea ice melted back to the smallest area since records began last September. Hurricane Sandy, whose fury is generally attributed to effects of climate change that helped it become as big as it was, devastated shores of New Jersey and New York and those populations have been having a grim winter – the richest nation on the planet cannot cope easily with the types of storms we are now seeing. Australia is currently suffering through a heat wave and fire season of extreme severity. The Sydney Morning Herald reported on 8th January that temperatures were literally off the chart. To quote Australia’s Climate Commission as Science did, “the length, extent and severity of the current heatwave are unprecedented in the measurement record.”
The Australian Bureau of Meteorology had to add new colors to its chart in order to cover the 54oC temperatures recorded in early January. Photo © Australian Bureau of Meteorology
Tasmanian fires Photo © Richard Jupe, The Mercury
Shorncliffe, Brisbane flooding. Photo © Michelle Smith
Australia’s weather has now become very wet and windy, so the fires are replaced by flooding and tornadoes from northern Queensland south to Sydney region all caused by Oswald, the first cyclone of the year to hit that coast. Conditions on the northeast coast are being described as the worst in 30 years, and the insurance costs due to flooding in Queensland ($50M) have already equaled the cost of the fires in Tasmania. In North America we are experiencing a winter characterized by swift cycles from milder than usual to extreme cold exactly as predicted by Chuck Greene in Scientific American last fall – the warming Arctic is destabilizing the jet stream so that it wobbles from north to south more rapidly and extremely than in the past.
Collision, January 26th on Hwy. 401, about 80 kilometres east of Toronto. Many cite severe weather as the cause. Photo © Karen Longwell/Northumberland
The world’s oceans also had their 10th warmest year (sea surface temperature) despite this being another La Nina year when tropical waters are generally cooler than usual. 2012 was the warmest La Nina year on record. I could go on, but I think you all get the picture.
Now to the politics. There is a little good news, and plenty of bad. The World Economic Forum released its annual assessment of the global economy in the run-up to Davos, and listed climate change and other environmental problems along with sluggish economic growth as the top two issues of concern. It noted that ignoring either of these would cause problems for overall prosperity. Also good news is the evidence that the economic community is beginning to adjust to slow global economic growth, even if it is not embracing a no-growth future. Nothing beats getting your perspective better aligned with reality.
But on the bad side is the refusal of countries like Canada to recognize that a) one cannot base economic prosperity on extraction and export of dirty tar sands oil, and b) that economic woes are not always the fault of someone other than the government in charge. Canada’s economy is growing more sluggishly than anticipated largely because the tar sands are not yielding the royalty and tax revenue that Alberta and the Harper government both were counting on. As I said some time ago, Canada could learn from Norway, but that is not happening. While Canada will be a little quieter at Davos (Harper is not even going, although he used that platform last year to ‘educate’ Europe and the US), and while the Alberta premier talks of belt tightening, the media this week are full of articles extolling the value of the tar sands to Canadians, the benefits to parts of Canada outside Alberta, and the need for more pipelines including Northern Gateway and Keystone XL. Increasingly the signs from Washington are that Keystone will be approved, but the fact remains that we do not need more pipelines if the expansion plans for the tar sands project are scaling back because of changed economic circumstances. Members of Parliament such as Liberal David McGuinty need to stop mouthing the propaganda being provided by the fossil fuel industry, and opposition to growth of the tar sands industry needs to ramp up, rather than fade away as if it were un-Canadian. It is NOT that the tar sands are contributing an enormous percentage of the GHG released globally. It is that they are dirtier than any other form of oil (both in GHG and water pollution), and that Canada cannot meet its own very modest commitments on GHG emissions while still pushing for a tripling of production. The Harper government is being irresponsible in building its economic policy on tar sands revenues.
Also on the bad side is some information on the new US House of Representatives appointees to its Committee on Science, Space and Technology. As reported by Science, the House has announced that Indiana Republican Bucshon will head its research subcommittee, Wyoming Republican Lummis will head the energy portfolio, and Kentucky Republican Massie will head the technology portfolio. Bucshon is a deep skeptic of climate change science, Lummis is a strong fossil fuel advocate who does not believe humans are causing climate change, and Massie is a Tea Party fan. It will be interesting to see how Obama deals with a House of Representatives with people like these in charge of science and technology.
And the science keeps piling up, telling us that the problem of climate change is serious and getting worse, and that we are rapidly running out of time to prevent a dire future. Let’s talk about four papers out within the last couple of weeks.
The first is a major paper on the role of black carbon (soot to you and me) in climate change that has just been posted on-line in Journal of Geophysical Research: Atmospheres. It’s open access, but the pdf is 286 pages long. Richard Kerr provided a one-page summary in Science of 25th January.
Tami Bond and 29 co-authors from universities across the US, UK, Germany, Austria, Switzerland, Norway, Japan, China, and India have undertaken a massive study to remedy what has been a significant problem in climate projections – how to account for the effects of soot in the atmosphere or on the surface of snow and ice. The problem exists because soot both shields the planet from sunlight and absorbs that sunlight giving off heat, and also affects cloud formation and melting of ice and snow. The uncertainty has been in the relative importance of these positive and negative effects on warming.
Diagram from Bond et al, J. Geophys. Res: Atmos, 2013 showing the complexities of impacts of black carbon on the climate.
Turns out, according to the authors, that soot may be the second most important contributor to warming behind CO2. The warming effect of substances in the atmosphere is measured as the ‘net radiative forcing’ measured as Watts per square meter. They estimate that, whereas CO2 at current (=2005) atmospheric concentrations provides a net radiative forcing of +1.56 W m-2, current emissions of black carbon have a net radiative forcing of +1.1 W m-2 including all sources of warming: absorption of solar radiation, influencing cloud formation processes, and altering the melting of snow and ice cover. (Methane, CH4, is third at +0.86 W m-2.) Furthermore, most of the soot in the atmosphere at present is due to human activities – the estimated preindustrial level is about 24% of the current total. There remain large variances among some of their estimates, but the overall picture is clear – soot from diesel
Chart from Bond et al J Geophys Res. Atmos. 2013, showing the distribution of emissions of black carbon among sources and regions of the planet
engines, biofuel, residential solid fuel burning, and open burning including naturally occurring forest and grass fires is a major factor in global temperature. Furthermore, because soot remains in the atmosphere for a relatively short time compared to CO2 or CH4 actions to reduce emissions of soot will have rapid effects on climate. It’s clear from this paper that some actions we can take to reduce the release of black carbon into the atmosphere will have real effects reducing the warming of our climate (plus it might reduce smog as well). At the same time, this detailed study makes it clear that some mitigation strategies will be far more useful than others. There is lots of complexity in this story, and there will undoubtedly be new discoveries down the road. Still, in a way, this study is positive news because it highlights the value of tackling emissions of black carbon as a climate mitigation strategy.
Not so two other studies. Joeri Rogelj, of the Institute of Atmospheric and Climate Sciences at ETH Zurich, together with three colleagues, has published a paper in Nature Climate Change (online on 16th December) which examines the emissions levels in 2020 that will be required if we are to limit warming to 2oC during this century. Thomas Stocker published a much simpler analysis which asks much the same question in Science for 18th January 2013. [Added 31 Jan: David has kindly sent me a link to an open copy of Stocker’s paper here. Thanks, David.] Both papers are attempts to flesh out the argument that delay is costly, and that the climate problem becomes more difficult to solve the longer we delay. Intuitively this argument makes sense, but people who have to plan changes to national economies need more information than that. The Rogelj paper has used a complex analysis that takes into account technological feasibility while assessing political and economic costs of acting. It is very much a real-world attempt to evaluate alternative approaches and the various components of the costs of delay. It is also quite a complex paper to read, and I found an article discussing this work by Stephen Leahy in the Guardian particularly useful in identifying the major messages. (Message to the science community – we do need to work harder to write so we can be understood.)
Still Rogelj and co are quite explicit about the mitigation steps needed. They write, “First and foremost, improving the efficiency of energy systems is key…. Substantially limiting energy demand has the largest impact on our feasibility window, in that it significantly relaxes the necessary emission reductions that must be achieved by 2020. Second, …. the availability of CCS and the immediate participation of all regions in global mitigation efforts also seem to be very important factors. It is infeasible to achieve 2oC in our framework if these two critical assumptions are not realized, unless demand is low.” We have got to cut demand for energy, as well as do everything possible to move away from energy sources that emit CO2.
According to Rogelj and co, there is a window of emissions rates between 41 and 47 giga tonnes CO2 equivalent per year which must be reached by 2020 if we are to be reasonably certain of being able to keep warming under 2oC during this century. Emissions are currently about 52 giga tonnes CO2 equivalent, and all the targets for reduction that countries have announced will not bring the rate below 55 gigatonnes CO2 equivalent in 2020 (yes, that is more than at present, because there is so much growth in energy use anticipated in developing countries). Let me say that again. Achieving all announced emissions target will not get us to this window in 2020. And remember that at the Durban climate conference in December 2011 (and reconfirmed in Doha last year), the ‘major achievement’ was to come back in 2015 with a plan that could be adopted for further reduction efforts commencing in 2020! We are not on target to get to the window we need to get to. Failure to lower emissions to the required level in 2020 means that a) a 2oC limit may well be exceeded, and b) meeting it requires far more aggressive, far less certain, and far more expensive actions. We are currently playing very stupid.
Stocker’s much shorter and simpler paper adopts a simple model in which global GHG emissions rise exponentially until the date when a ‘greenhouse mitigation strategy’ (GMS) is adopted globally. They then fall exponentially. His questions are, how far into the future can we adopt this GMS and still reach our 2oC (or any other agreed) warming target, and do we have to mitigate more aggressively if we wait
Figure from Stocker, Science, 25 January 2013 showing combinations of starting year of GMS mitigation effort and level of mitigation effort (as percent reduction of GHG emissions per year).
longer before GMS begins. He uses the approximately proportional relationship between the amount of warming achieved and the cumulative total of all GHG emitted since the start of the industrial revolution which has been borne out by a broad range of climate models, and analyses for time to GMS and extent of mitigation effort. As his figure shows quite simply, we are rapidly running out of time if we want a 2oC warming limit, especially if we consider that a 5% reduction in emissions per year is about the maximum that could be achieved while keeping economies functioning. It’s not the same message numerically, but it is very much in agreement with that of Rogelj and colleagues. We are rapidly approaching a situation in which we will no longer be able to keep climate change to a reasonable amount (and remember also that many ecologists are now saying 2oC is too high).
The final article for today is by Steven Davis of UC Irvine and three colleagues. It was published in Environmental Research Letters in early January, and I learned about it through a short summary article by Eli Kintisch in Science for 11 January. The Davis article is titled, ‘Rethinking wedges’, a title which gives nothing away unless you happen to know of a paper in Science of 2004 by Socolow and Pacala of Princeton University. Their paper was called, ‘Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies’, which is also a bit obscure.
What Socolow and Pacala did was to suggest that we could stabilize annual GHG emissions at 2004 levels if we embarked on seven major mitigation initiatives, each eliminating emission of about 25 billion tonnes of CO2 over five decades. These seven initiatives could be thought of as seven wedges that together summed to the total amount of CO2 that must be contained. It was a simple approach that took a large problem and chopped it into smaller, if not quite bite-size, chunks, and it conveyed a hopeful optimism about the future.
Steven Davis was a 26 year old graduate student in 2004. Rethinking Wedges is his effort to look at the problem with the benefit of more precise information on the extent of mitigation needed, and on the rate at which emissions are increasing. He wanted to see whether there was much change in the basic message – seven interventions each reducing emissions by about 25 billion tonnes CO2. So, what do we expect? Maybe we will need a few more wedges; maybe not? In their paper Davis and colleagues show that this problem now requires 31 wedges – or a total mitigation effort equivalent to preventing the emission of 25 x 31 = 775 billion tonnes of CO2 over the next 50 years. They discuss the various reasons
Two of four panels from the Kintisch summary in Science, comparing the 7 wedges of Socolow and Pacala to the 31 wedges of Davis et al. The goal in both is to keep warming to 2oC at 2050. Socolow and Pacala under-estimated the amount of mitigation required (hence the ‘phase-out’ wedges). The simple message from these two panels is “look how much bigger the problem has become in 9 years”.
for the extra wedges. Many of them are due to our lack of action in the years since 2004. Their concluding words are chilling: “Current technologies and systems cannot provide the amounts of carbon-free energy needed soon enough or affordably enough to achieve this transformation. An integrated and aggressive set of policies and programs is urgently needed to support energy technology innovation across all stages of research, development, demonstration, and commercialization.”
Don’t let anybody tell you that we can deal with climate change later. We cannot; it has to be now. Every one of these three papers comes to the same conclusion (some with more elegance or more detail than others). And one thing they do not dwell on is that 2oC warming is more than twice what we have already experienced. I fear the weather reports in 2050 are going to be truly exciting.