Long-term response of oceans to CO2 removal from the atmosphere : Potsdam Institute, Nature Climate Change : Nature Publishing Group

Long-term response of oceans to CO2 removal from the atmosphere : Nature Climate Change : Nature Publishing Group.

Greenhouse-gas emissions from human activities do not only cause rapid warming of the seas, but also ocean acidification at an unprecedented rate. Artificial carbon dioxide removal (CDR) from the atmosphere has been proposed to reduce both risks to marine life. A new study based on computer calculations now shows that this strategy would not work if applied too late. CDR cannot compensate for soaring business-as-usual emissions throughout the century and beyond, even if the atmospheric carbon dioxide (CO2) concentration would be restored to pre-industrial levels at some point in the future. This is due to the tremendous inertia of the ocean system. Thus, CDR cannot substitute timely emissions reductions, yet may play a role as a supporting actor in the climate drama.

“Geoengineering measures are currently being debated as a kind of last resort to avoid dangerous climate change – either in the case that policymakers find no agreement to cut CO2 emissions, or to delay the transformation of our energy systems,” says lead-author Sabine Mathesius from GEOMAR Helmholtz Centre for Ocean Research Kiel and the Potsdam Institute for Climate Impact Research (PIK). “However, looking at the oceans we see that this approach carries great risks.” In scenarios of timely emissions reductions, artificially removing CO2 can complement efforts. “Yet in a business-as-usual scenario of unabated emissions, even if the CO2 in the atmosphere would later on be reduced to the preindustrial concentration, the acidity in the oceans could still be more than four times higher than the preindustrial level,” says Mathesius. “It would take many centuries to get back into balance with the atmosphere.”

We need to grow 50% more food yet agriculture causes climate change. How do we get out of this bind? | Global Development Professionals Network | The Guardian

We are trapped in a vicious cycle: we will need to grow 50% more food by 2050 to feed 9 billion people but agriculture, which is paradoxically vulnerable to climate change, generates 25% of heat-trapping greenhouse gas emissions that lead to climate change. The more we grow using conventional methods, the more we exacerbate the problem. It’s time for a climate-smart agriculture but first we must address a few man-made problems.

First, there is a frustrating lack of attention paid to agriculture in the current global climate talks leading up to the Paris conference later this year. By definition, food production affects all countries, rich and poor, and it is hard to imagine any effective post-Kyoto climate change agreement that ignores 25% of the problem. So, we need a climate change agreement where agriculture is a big part of the solution, and delivers a triple win: higher agricultural productivity to feed more people and raise the incomes of poor farmers – especially women, greater climate resilience, and reduced greenhouse gas emissions.

via We need to grow 50% more food yet agriculture causes climate change. How do we get out of this bind? | Global Development Professionals Network | The Guardian.