JOHANNES LEHMANN: Hello. I'm Johannes Lehmann, professor of soil science at Cornell University. I'm so pleased to address you at a moment where the bilateral agreement on greenhouse gas emission reductions between the US and China has sent a clear signal for action. Specifically today on World Soil Day, December 5, which kicks off the United Nations International Year of Soils 2015. I'm eager to discuss with you where soil fits into a comprehensive strategy to mitigate climate change.
The science is absolutely clear. The global climate is changing faster than anticipated, and we have to do something about it. The silver bullet will prove elusive, and only a concerted international effort will provide us with a chance to mitigate and adapt to climate change by building a deep toolbox of approaches to reducing greenhouse gas emissions.
But it is increasingly becoming clear that reducing emissions alone, while an indispensable prerequisite of any successful mitigation strategy, will not be sufficient. And an active withdrawal of atmospheric carbon dioxide will need to be part of managing climate change through, for example, carbon sequestration. I share the concern expressed by progressive thinkers that a scenario where we are forced to take drastic steps may prove disastrous without having done due diligence on the risks and opportunities of a portfolio of sequestration options.
This year's IPCC report made impressive progress in laying out the need for carbon sequestration and provided the first data on what efforts are needed to reduce atmospheric carbon dioxide. The principal pathway to achieving this carbon drawdown put forward in the report is bio-energy with carbon capture and sequestration, or BECS. The technical feasibility and cost-effective deployment are still not proven. Pilot projects should be put on the road without further delay.
However, additional avenues must be explored. Pyrolysis bio-energy with biochar return to agricultural soils is a technically feasible approach to start sequestering carbon dioxide now with little development time to initial deployment needed in comparison to BECS. Such a strategy would not only remove carbon dioxide from the atmosphere, but also be able to restore soil health and increase crop productivity in degraded areas.
Applying stringent sustainability criteria to biomass use yields a potential to withdraw one gigaton carbon per year from the atmosphere over the coming 100 years using biochar sequestration with more being possible and less being likely given financial constraints. This may prove the stopgap measure that will allow a safe transition to a low or no [INAUDIBLE] emissions society. There will be trade-offs between maximizing energy generation by using biomass and sequestering carbon with biochar. This must be stated very clearly.
Opportunities and constraints have to be investigated now to be ready when far-reaching decisions about a comprehensive global strategy to carbon sequestration are made. The costs must be evaluated at scale of implementation with a clear pathway to crop yield increases by biochar addition to soil, which brings me back to my point from the beginning. Do we want to utilize biomass only for energy or rather a sustainability package that helps transition into climate-smart agriculture?
Restoring and maintaining healthy and productive soils should in my view be prioritized, especially if it generates the same climate benefits at comparable costs. Thank you for your attention, and happy World Soil Day.
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Cornell soil scientist Johannes Lehmann speaks about climate change mitigation strategies for the UN COP 20 Climate Change Conference held Dec. 2014 in Lima, Peru. Lehmann addresses the potential of biochar as an important and immediate option for sequestering carbon and improving soil health.