We are continually faced with a series of great opportunities brilliantly disguised as insoluble problems.
– John W. Gardner
The quote above came to mind when I read ‘Worst Case’ Scenario: New Report Says World Is Warming Faster than Thought:
Two degrees — that value has long been the guideline for international climate policy. Were the increase in average global temperatures held below 2 degrees Celsius (3.6 degrees Fahrenheit), then drastic climate change and long-term irreversible damage — like the melting of Greenland’s glaciers — could still be avoided. Or so it was thought.
…
In 2007, the IPCC assumed that the earth’s average temperature could increase anywhere from 1.8 to 4.0 degrees Celsius by the end of this century — depending on which strategy the international community adopts and by how much greenhouse gas emissions are reduced.
According to the current findings, the world is currently on track for the worst-case scenario — the dynamics of climate change are already larger than feared.
To be on the safe side, people should adjust for a three, four or even five degrees of warming, PIK head Schellnhuber recommended in March at the Copenhagen congress. Should he be right, extreme weather resulting from rising global temperatures could be even more dramatic than assumed up until now.
In the past, the IPCC prepared an entire spectrum of possible emissions scenarios for this century. According to the new report, “some climate indicators are changing near the upper end of the range indicated by the projections or, as in the case of sea level rise, at even greater rates than indicated by IPCC projections.” The report continues, “current estimates indicate that ocean warming is about 50 percent greater than had been previously reported by the IPCC.”
Konrad Steffen, professor for Environmental Science at the University of Colorado in Boulder, explains what that means. “The forecast for the year 2100 probably needs to be revised at least by a meter or more,” he says.
Schellnhuber, who is also a climate consultant for the German government, says he is worried “that we still aren’t seeing a large portion of the unavoidable global warming.” Dirt particles in the atmosphere, especially sulphate aerosols, have created a certain cooling effect and has prevented a stronger temperature increase at the moment. “If we were to ever install sulphur filters all over the world, then we would already be at 2.5 degree warming,” the physicist said.
If this report sounds hauntingly familiar, it is. I mentioned it briefly just five days ago (Document alert: New synthesis report), and provided a direct link to the 39 page, 5.7MB report in PDF format.
What I didn’t do, however, was give this report the attention it deserved. Hopefully this post will help close that gap in my performance.
While I strongly urge you to read the whole document, let me quote at length the portion (page 18) that directly addresses the main issue brought up in the above article:
The goal of constraining warming to an average global temperature increase of no more than 2°C above preindustrial levels plays a central role in current discussions about appropriate climate policies. As described in the previous section, a 2°C warming would, in itself, introduce considerable risk to human society and natural ecosystems. Nevertheless, the facts that global average temperature has already risen by about 0.7°C and that greenhouse gas emissions from human activities are still increasing (Box 2) render the achievement of a more ambitious goal very difficult. Due to inertia in the climate system alone, the 2007 IPCC Report argues that a global temperature increase of about 1.4°C above preindustrial levels is inevitable. There is also inertia in human systems but this is harder to quantify and it is not known how quickly or dramatically society can or will reduce greenhouse gas emissions.
What level of emission reductions is needed to retain climate change on the right side of the 2°C guardrail? The IPCC estimated the level of atmospheric concentrations of greenhouse gases at which the global average temperature rise would be contained within various ranges (Table 1). The concentrations are given both as CO2 and CO2-equivalents. CO2-equivalents include the combined warming effects of CO2 and the non-CO2 greenhouse gases (excluding water vapour) as well as the net cooling effect of aerosols in the atmosphere. CO2-equivalents are expressed as the equivalent amount of CO2 required to give the same net warming as that created by these other gases and aerosols. Aerosols are small particles suspended in the atmosphere that reflect the sun’s incoming radiation and thus have a cooling effect. As air pollution regulations become more stringent and the amount of particles emitted to the atmosphere from human activities decreases, the cooling effect of aerosols in the atmosphere will also be reduced.
According to the IPCC analysis, atmospheric CO2 concentration should not exceed 400 ppm CO2 if the global temperature rise is to be kept within 2.0 – 2.4°C. Today, the CO2 concentration is around 385 ppm, and is rising by 2 ppm per year. The 2007 concentration of all greenhouse gases, both CO2 and non-CO2 gases, was about 463 ppm CO2-equivalents. Adjusting this concentration for the cooling effects of aerosols yields a CO2-equivalent concentration of 396 ppm. A recent study estimates that a concentration of 450 ppm CO2-equivalents (including the cooling effect of aerosols) would give a 50-50 chance of limiting the temperature rise to 2°C or less.
Thus, atmospheric CO2 concentrations are already at levels predicted to lead to global warming of between 2.0 and 2.4°C (Table 1). If society wants to stabilise greenhouse gas concentrations at this level, then global emissions should, theoretically, be reduced by 60-80% immediately, the actual amount being dependent upon the amount that will be taken up by oceans and land. Given that such a drastic immediate reduction is impossible, greenhouse gas concentrations will continue to rise over the next few decades. An overshoot of the atmospheric greenhouse gas concentrations needed to constrain global warming to 2°C is thus inevitable. To limit the extent of the overshoot, emissions should peak in the near future. Recent studies suggest that if peak greenhouse gas emissions are not reached until after 2020, the emission reduction rates required thereafter to retain a reasonable chance of remaining within the 2°C guardrail will have to exceed 5% per annum. This is a daunting challenge when compared to a long-term average annual increase of 2% in emissions (Box 2). The conclusion from both the IPCC and later analyses is simple – immediate and dramatic emission reductions of all greenhouse gases are needed if the 2°C guardrail is to be respected.
Short-term financial concerns, political and institutional constraints and lack of public awareness and concern are the greatest barriers to immediately initiating ambitious emission reduction. There is still disagreement in the economics community as to whether climate change is simply an externality like any other or is fundamentally different from anything humanity has ever faced. There is also disagreement about how to appraise the costs of mitigation as compared to the future costs of inaction, and how to evaluate the risks of climate change. Nevertheless, a growing number of analyses indicate that the costs of both adapting to and mitigating climate change will increase if action is postponed (sessions 32 & 52), (Box eight). Generally, economic analysts agree that the uncertainty about the extent of future climate change is not a rational reason for delaying programs to curb emissions. Existing economic structures and interests, however, can often prevent effective climate policy action.
I have resisted the argument that surely everyone who reads this site has heard, namely that we have to put at least as much resource into adaptation as we do mitigation (i.e. reduction of CO2 emissions). This line of thinking usually falls into one of two categories: Cost efficiency or inevitability.
Cost efficiency, which sounds cold blooded, essentially says that while moving people away from coastlines, building desalination plants and sea barriers, etc. are certainly not cheap, they still deliver more human impact avoidance per dollar than simply reducing CO2. In other words, it’s economics in its purest form: Finding the optimal allocation of scarce resources to achieve the most good. As much fun as it is to bash economists in some corners of the Internet, it’s undeniably true that when you have a choice of preventing X or X + Y human suffering for the same cost, and you’re spending all that you can afford, then only a fool or a sadist would take the first option. Deciding which of many possible combinations of actions to take is a classic exercise in multivariate optimization.
The inevitability argument is much simpler: No matter what we do to reduce the emission of greenhouse gases, climate chaos is going to be bad. As in really bad, so it makes no sense to ignore adaptation efforts and focus almost exclusively on mitigation, since that won’t be enough. (These arguments are really the same, as they’re merely claiming that the best way to respond to this quickly evolving situation is not a monolithic approach; they’re often presented as unique views, so I’m preserving that dichotomy.)
Suddenly, I’m no longer sure it makes sense to reject these arguments. If the best, leading edge and peer reviewed research, like the report above, says we’ve already created a world where more than the magic two degrees of warming is locked in, then at the very least we have to start considering some very nasty choices that a lot of people still think are plot elements from a bad science fiction movie and not reality. To pick just two examples: What do we do about all the large population centers on coastlines around the world? And how do we address the looming fresh water crisis that will very likely affect well over a billion human beings in the next few decades?
As for the emissions involved, remember that 1 ppmv of CO2 in the atmosphere is about 7.79 billion metric tons (see Life in the Metricene), so increasing from 385 ppmv now to the 400 ppmv limit mentioned above requires “only” an additional 116.85 billion metric tons. And the world emits about 30 billion metric tons of CO2/year, a good portion of which would effectively be absorbed by the oceans and plant life. That’s assuming we don’t get a sizable boost in CO2 (and/or methane) from the permafrost bomb starting to go off (see Life in the Metricene, CO2 checkpoint, and Methane checkpoint).
Again: Please read the report, and let’s all hope that John Gardner was right and this terrifying situation turns out to be one heck of a great opportunity.
