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Have We Already Moved On to Climate Plan B?

Written by John Field, 2015-2016 Sustainability Leadership Fellow and Postdoctoral Fellow, Department of Mechanical Engineering, CSU.

After two decades of failed efforts to reign in greenhouse gas emissions, avoiding the worst of climate change may now depend on carbon-negative biofuels and other uncertain technological fixes.

It has been more than a century since a Swedish scientist named Svante Arrhenious predicted that increases in the level of carbon dioxide in the atmosphere would warm the surface of the Earth through the greenhouse effect. Such an increase in atmospheric CO2 due to the cumulative effects of humans burning fossil fuels and clearing land was first observed in 1960, and over the next several decades climate science emerged as an important research discipline. By the 1980s consensus was building within the scientific community that climate change was a threat, and the issue came to broader public awareness thanks to the efforts of civic-minded scientists like James Hansen and Stephen Schneider. Recognizing the global nature of the issue and the need for international cooperation, the Intergovernmental Panel on Climate Change (IPCC) was formed by the United Nations in 1988 to advise the world’s governments on the state of scientific knowledge around climate change.

Since then the IPCC has periodically released reports compiling the best science on quantifying the greenhouse effect, understanding its implications for human societies and natural ecosystems, and exploring how we might respond to the issue. These reports typically contain stern warnings about the dangers of climate change coupled with upbeat assessments of our ability to reduce our emissions and mitigate the problem. Assessment Report 2 (AR2), published in 1995, warned that “entire unique cultures might be obliterated” due to “dangerous anthropogenic interference with the climate system”, but noted that “a carefully selected portfolio of national and international responses of actions aimed at mitigation, adaptation and improvement of knowledge can reduce the risks.”  That optimistic tone continued in subsequent reports: AR4 in 2007 reported that the cost of reducing emissions “corresponds to slowing average annual global GDP growth by less than 0.12 percentage points” and most recently, a follow-up conference to AR5 noted that “the additional investment required to transition to clean energy can be a small fraction” of our overall investments in the energy sector.

However, anyone familiar with the data knows that we have largely failed to heed these warnings, and total emissions of CO2 and other greenhouses gases have been consistent with worst-case scenarios. So how then does the IPCC continue to deliver optimistic projections after decades of accelerating—rather than falling—emissions? In part, it now assumes that the world economy can shift to renewable energy sources much more quickly than was previously though possible. The optimistic projections also rely heavily on this machine, and others like it:

That photo is from a corn ethanol facility in Illinois where the CO2 gas by-product of ethanol fermentation is being compressed to extremely high pressures and injected into geological formations deep underground for permanent storage.  Compressing and storing CO2 underground is known as Carbon Capture and Storage (CCS), a technology widely pursued by the coal industry as a way to stay alive in an age of GHG regulations and carbon taxes. When applied to CO2 derived from the production of biofuels or power from plant matter, you get Bioenergy with Carbon Capture and Storage, or BECCS. The idea is that plants sucked up CO2 from the atmosphere during their growth, and that storing the CO2 resulting from fermenting or burning those plants is a form of “negative emissions”, a net transfer of carbon out of the atmosphere into underground storage (with a whole bunch of caveats around how those plants were grown and how much energy was used in the process). 

The graphic below highlights just how pervasive BECCS is becoming in IPCC’s future greenhouse gas emissions scenarios. Those scenarios (left) that avoid the worst effects of climate change and limit surface temperature increase to <2°C (i.e., those in blue and green) are usually associated with scaling up BECCS over the next century to the point that it provides 10-30% of all human energy demands (right), in the same ballpark as natural gas currently does.  In effect, the latest IPCC projections continue to get to an optimistic result through assumptions that we will be able to transition to a carbon-free energy system much more quickly than previously assumed, and that BECCS and other negative emissions technologies will be widely deployed and correct for any overshoot.  That’s a tall order for technologies that have never before been deployed at large scale!

Now if reading this makes you a bit uncomfortable, you’re not the only one. Two scientists have recently cried foul on the IPCC process through editorial letters in the world’s most prominent scientific journals. In May of this year Oliver Geden, a German climate scientist and civil servant, took the group to task for giving in to political ‘pressures that undermine the integrity of climate science’ and peddling ‘false optimism’ based on ‘dubious concepts’ such as negative emissions technologies. He writes in the journal Nature:

Climate researchers who advise policy-makers feel that they have two options: be pragmatic or be ignored… The climate policy mantra — that time is running out for 2 °C but we can still make it if we act now — is a scientific nonsense. Advisers who shy away from say­ing so squander their scientific reputations and public trust in climate research.

Similarly, just last month English climate scientist Kevin Anderson wrote in Nature Geoscience (nice summary here) to point out that the IPCC projections are full of errors and overly optimistic assumptions resulting in ‘incremental escapism’ and ‘deus ex machina’ solutions, declaring:

As scientists, we must… combat the almost global-scale cognitive dissonance in acknowledging [our work’s] quantitative implications. Yet, so far, we simply have not been prepared to accept the revolutionary implications of our own findings, and even when we do we are reluctant to voice such thoughts openly… It is not our job to be politically expedient with our analysis…

Those are powerful critiques, with language much more forceful and direct than we often hear from the scientific community. 

Now is a conflicted time for many of the scientists doing work on these topics. My own research focuses on the caveats around how to sustainably produce plant material at large scale from various sources that would be required for a scale-up of BECCS. It’s exciting to think that someday this work might have relevance in the fight against climate change, and I hope that continued funding allows us to develop practical, sustainable solutions in this area. But at the same time, I hope that if these technological fixes ever become a reality it’s because we collectively make a conscious choice to do so, not because false optimism backed us into a corner. 

Interested in learning more about BECCS and how they might play into future emissions scenarios? Check out these excellent pieces by Brad Plumer at Vox or Chris Mooney at the Washington Post. 


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