Significantly limiting humanity’s impact on the global climate is quite simply an enormous task. Unfortunately, thanks to budget austerity and federal gridlock, any hope of implementing sweeping U.S. climate/energy policy has been optimistically pushed back to 2013 or beyond (though some incremental improvement is possible). And even the most hopeful observers of the recent global climate negotiations in Durban find little real progress towards reducing emissions. Now more than ever, it is time to take a hard look at where we stand and figure out how to match our policies to our climate goals.
Amongst climate scientists and advocates of climate policy, a growing recognition is taking hold that the current trajectory of global emissions will almost certainly lead us to a world of dangerous climate change impacts. For some, this means coming to terms with the fact that holding total global warming to less than 2°C, a commonly adopted “line in the sand” drawn by many climate advocates, has become nigh-impossible.
As a number of scientific articles have shown, most recently by Kevin Anderson and Alice Bows in the Journal of the Royal Society, limiting the world to 2°C warming most likely requires peaking total global carbon emissions in the next 5-10 years followed by immediate reductions to near-zero by 2050 (see Anderson and Bows emission trajectory options here, via David Roberts, and by David Hone here). It is now fairly obvious that the lack of global progress on decarbonization has likely pushed this timetable out of reach, prompting some recent soul searching amongst many climate advocates (the two of us included).
Is this realization a game changer for climate policy? Yes and no.
That 2°C constituted a clear threshold below which global warming would be “acceptable” and “safe” and above which it was “dangerous” was always a fairly arbitrary conceit. While climate science can effectively inform us about the range of possible consequences of a warming world, there is a large amount of irresolvable uncertainty inherent in climate forecasting. From the basic sensitivity of atmospheric temperature to CO2 on through to efforts to predict regional-scale impacts, a chain of “error bars” multiply to give us a fairly uncertain picture of our future warming world. And of course, what constitutes “dangerous” climate change was always a human value judgment, not a matter of precise science.
In the face of such inherent uncertainty, drawing “bright line” thresholds of “safe” versus “dangerous” warming has always been a fraught exercise, an effort to grasp for certainty in an uncertain world. Instead, we are now, as we have always been, left to act in spite of and indeed because of this inherent uncertainty.
We have long ago learned enough from climate science to know that global greenhouse gas emissions must be reduced as quickly as possible and that climate change presents a clear threat. Damaging climate impacts are likely already occurring even at today’s 0.8°C warming, and each degree of greater warming will intensify future impacts. Greenhouse gases must therefore be reduced as quickly as possible.
Hurtling towards a 2°C warmer world does little to change this fundamental calculus. After all, many climate advocates have variously selected 350 PPM or 1.5°C as their “bright line” goal (outcomes we’ve long since overshot), and yet the core calculus for these advocates is again the same: we must nonetheless still strive to reduce emissions as quickly as possible. And even those who see 2°C as a now-impossible goal must recognize that each 10th of a degree of eventual warming after that point matters a great deal. There is much that can still be done to reduce future climate impacts, and those efforts will depend far more on how quickly we can accelerate declines in the carbon intensity of the global economy than on what target we pick today for eventual warming. In any case, we must reduce emissions as quickly as possible.
At the same time, the widespread recognition that we are now firmly on a path towards “dangerous” warming should change one fundamental concept: while many climate advocates have operated under the assumption that we could hold future warming to “safe levels,” and thus must focus principally on “mitigating” climate change by driving emissions reductions, others have long argued that we must simultaneously begin to prepare for a warming world and significant impacts already in store. We must begin to “adapt” or build “resilience” to climate and weather extremes, the proposition goes, in order to minimize the damage wrought by future warming.
For a long time, those arguing for proactive adaptation were ignored or relegated to the sidelines of global climate discussions. In the worst cases, those arguing for adaptation efforts were treated as dangerous influences out to a fear that belief that the world could “adapt” to climate impacts could undermine the motives for mitigation. (In recent years, this attitude has thankfully begun to shift.)
Now, all climate advocates should be clear: dangerous warming is coming, if not already here today. No longer can climate adaptation and resilience be treated as secondary priorities. To do so would be morally reprehensible, equivalent to willfully neglecting preparations for a storm we all know is coming.
While climate science is most uncertain when it comes to the regional-scale impacts we care most about, we have a fair idea of the range of likely impacts in store for us now. The best estimates indicate that our current emissions trajectory poses a significant risk of eliminating many unique ecosystems including coral reefs, large swaths of forests, small island communities, and arctic habitat. Extreme weather events like floods, heat waves, droughts, and wildfires will become much more frequent and have greater regional impacts throughout the world. Agricultural yields may be strained. Specific populations, such as those less economically developed or in lower-lying regions will be at a very high risk of impact and hundreds of millions of people will potentially be adversely affected by events like coastal flooding, saltwater infiltration into agricultural lands, and sea level rise. Climate models also point to a more-likely-than-not probability that even greater impacts will result from feedback mechanisms such as permafrost and ice sheet melting beginning or accelerating, unleashing further warming.
In other words, our future holds a much different climate and world, as we’ve simply waited too long to mitigate away all potential impacts. One might call this an inconvenient truth. And it means we must proactively prepare for this warming world as best we can. It is time to build climate resilience.
So what does our current climate outlook look like? It means first, we must redouble efforts to reduce global greenhouse gas emissions (and other climate destabilizing forces) as quickly as possible, and second, we must proactively prepare for a warming world.
The key questions are thus: how do we cut emissions as quickly as possible? And how do we build resilience to a changing climate?
In a series of posts, we will take up each of these questions. We will first consider whether the “brutal logic” of our current climate trajectory demands voluntary economic contraction, at least in the rich nations, as Grist.org’s David Roberts contends. Second, we will argue that successfully accelerating energy innovation to reduce the costs of low-carbon energy technologies is the key to accelerating how quickly we can reduce CO2 emissions. The pace of innovation matters far more than efforts to boost public support for climate mitigation, we will contend, even though such efforts are also important. Third, we will present a case for a proactive climate resilience effort, an effort that must take its place amongst our core climate policy efforts. And finally, we will discuss strategies to reduce forces other than CO2 that are potent contributors to global warming, yet can be reduced quickly and with significant near-term benefits while buying the world time to reduce CO2 emissions.