David B Lobell1, Uris Lantz C Baldos2 and Thomas W Hertel2
David B Lobell et al 2013 Environ. Res. Lett. 8 015012
© 2013 IOP Publishing Ltd
Received 28 August 2012, accepted for publication 10 December 2012
Published 12 February 2013
Successful adaptation of agriculture to ongoing climate changes would help to maintain productivity growth and thereby reduce pressure to bring new lands into agriculture. In this paper we investigate the potential co-benefits of adaptation in terms of the avoided emissions from land use change. A model of global agricultural trade and land use, called SIMPLE, is utilized to link adaptation investments, yield growth rates, land conversion rates, and land use emissions. A scenario of global adaptation to offset negative yield impacts of temperature and precipitation changes to 2050, which requires a cumulative 225 billion USD of additional investment, results in 61 Mha less conversion of cropland and 15 Gt carbon dioxide equivalent (CO2e) fewer emissions by 2050. Thus our estimates imply an annual mitigation co-benefit of 0.35 GtCO2e yr−1 while spending $15 per tonne CO2e of avoided emissions. Uncertainty analysis is used to estimate a 5–95% confidence interval around these numbers of 0.25–0.43 Gt and $11–$22 per tonne CO2e. A scenario of adaptation focused only on Sub-Saharan Africa and Latin America, while less costly in aggregate, results in much smaller mitigation potentials and higher per tonne costs. These results indicate that although investing in the least developed areas may be most desirable for the main objectives of adaptation, it has little net effect on mitigation because production gains are offset by greater rates of land clearing in the benefited regions, which are relatively low yielding and land abundant. Adaptation investments in high yielding, land scarce regions such as Asia and North America are more effective for mitigation.
To identify data needs, we conduct a sensitivity analysis using the Morris method (Morris 1991 Technometrics 33 161–74). The three most critical parameters for improving estimates of mitigation potential are (in descending order) the emissions factors for converting land to agriculture, the price elasticity of land supply with respect to land rents, and the elasticity of substitution between land and non-land inputs. For assessing the mitigation costs, the elasticity of productivity with respect to investments in research and development is also very important. Overall, this study finds that broad-based efforts to adapt agriculture to climate change have mitigation co-benefits that, even when forced to shoulder the entire expense of adaptation, are inexpensive relative to many activities whose main purpose is mitigation. These results therefore challenge the current approach of most climate financing portfolios, which support adaptation from funds completely separate from—and often much smaller than—mitigation ones.
When I tell someone I’m interested in climate change adaptation, I usually get one of two questions: “Cool. What does that mean?” or “Really? Have you given up on climate change mitigation/stopping climate change that easily?”
Photo. N. Palmer (CIAT)
The first is usually fun to answer; the latter can be frustrating. Many individuals working on climate change issues argue that a shift towards climate adaptation efforts undermines the continued, more pressing need to halt climate change, mitigate carbon emissions, do whatever we can to save us from some of the most terrifying projections for the future of our planet. Adaptation is distracting, defeatist, unambitious, some might say. But here is an undeniable reality– climate change is here and has been here. We live in an age of change and subsequent, desperately needed adaptation. Communities around the world are adapting to climate change as I write this, and through their adaptation, they are mitigating climate change. It seems obvious, yet sometimes it is necessary to state it anyways, that mitigation through adaptation and vice versa are inevitable notions (and fortuitous partners) all climate change and development practitioners, policymakers, and academics ought to embrace.
But what does this “mitigation through adaptation” look like? David Lobell at Stanford University’s Center on Food Security and the Environment gives us a great answer:
A new study shows that when it comes to agriculture, adaptation measures can also generate significant mitigation effects, making them a highly worthwhile investment.
Food production is big. If farmers fail to adapt to climate change we can expect to see more land being turned over to agriculture, in order to keep up with food demand. With this in mind, David Lobell, from Stanford University, US, and colleagues used a model of global agricultural trade to investigate the co-benefits of helping farmers adapt to climate change, thereby avoiding some of the emissions associated with land-use change.
Running their model to 2050, they show that an investment of $225 bn in agricultural adaptation measures can be expected to offset the negative yield impacts associated with predicted temperature and rainfall changes. But that’s not all – the model revealed that this investment would also save 61 million hectares from conversion to cropland, resulting in 15 Gtonnes carbon-dioxide equivalent fewer emissions by 2050. (From FSI, emphasis added)
The full findings can be found here.
The adaptation and mitigation communities should not be polarized, but must work together if there are any hopes of achieving meaningful change. So whether adaptation is helping us all mitigate carbon emissions by saving land from conversion to cropland, or by encouraging infrastructure updates that make our communities more resilient but also efficient (and therefore less carbon-intensive), it is clear that we all have a lot to learn from each other.
Aristotle would tell us that our “whole” can be greater than the sum of our parts.
These types of tensions are very common, and I might take a risk and say most common in the environment world. An emerging conversation outside the scope of this blog but worth a mention is that around a shift from a paradigm of sustainability to one of resilience. Should we “forget sustainability“? I don’t think so, just as we should not “forget” mitigation in our search for adaptation.
Sustainability, resilience, mitigation and adaptation. All have a place in a world facing climate change.
According to Jim Howell (2012 Quivira Conference speaker), one quarter to one half of the carbon that is currently being added to the atmosphere is due to industrial agriculture’s poor land use alone. Leaving land bare allows carbon from the soil to bond with oxygen in the air, creating carbon dioxide (CO2). This would not happen in nature, as there would always be plants covering the ground, protecting the soil carbon. CO2 is a greenhouse gas, which actively traps heat from the sun on the planet. We need some CO2 in the atmosphere to keep our planet warmer than the vacuum of space, but humans have exponentially increased atmospheric CO2 by burning fossil fuels, which are made of ancient atmospheric carbon stored up under the ground for millions of years. By burning fossil fuels, we have released so much CO2 that it has fundamentally changed the composition of our atmosphere. Scientists say that if we reach 450 ppm (parts per million) of CO2 in our atmosphere we will start an irreversible chain reaction of global warming, and our environment cannot sustain long term CO2 levels above 350 ppm. There are currently 394 ppm of CO2 in our atmosphere, which is the highest amount our planet has seen for at least 800,000 years, and possibly the highest earth has seen in the last 20 million years. At the moment, we are increasing atmospheric CO2 on an average of 2 ppm per year. At this rate, we will reach 450 ppm in 28 years. If we wish to continue living on planet Earth we must begin to not only reduce the CO2 we are releasing into the atmosphere, but we must reverse this process by sequestering atmospheric CO2. Building soil carbon actively sequesters carbon from the atmosphere by absorbing CO2 via plant photosynthesis. According to Fred Provenza, 2012 Quivira Conference Speaker, Every ton of humus (soil organic matter) created removes 3.76 tons of CO2 from the atmosphere.