Scientists now consider geoengineering, as well as curbing greenhouse gas emissions

What’s Next for Climate Action?Prominent scientists say researchers and policy makers need to focus more on adapting to warming and on controversial geoengineering techniques to limit it By Annie Sneed on December 16, 2016 , Scientific American, SAN FRANCISCO—Despite President-elect Donald Trump’s distaste for the Paris climate agreement, countries around the world are already working to ensure that the global temperature rise stays below 2 degrees Celsius. This week at the American Geophysical Union (AGU) conference here, several prominent scientists discussed the critical steps researchers and decision makers need to take now. They said reducing carbon emissions is important, of course, but countries worldwide must also put more energy into adapting to changing weather that even moderate warming will bring, as well as consider the potential of controversial geoengineering techniques to keep warming in check.

One of the primary goals of the Paris accord is mitigation—cutting or preventing greenhouse gas emissions. To help countries meet their emissions pledges, the international community needs to analyze how it can achieve “deep decarbonization,” according to Margaret Leinen, director of the Scripps Institution of Oceanography and president of the AGU. This means determining what emissions-reducing technologies and strategies will work best for a given country. As Leinen explained at a conference panel session, “We need to be able to evaluate these technologies quantitatively in order to understand which ones work, which ones are scalable and for what countries and energy economies they work for.”

Another major detail that still needs to be sorted out: how to track nations’ emissions, to make sure they’re sticking to their reduction targets. “We need to start asking, ‘Okay, how will you prove that you actually did what you pledged to do?’” Leinen told Scientific American after the panel. To do that, countries will have to have some kind of monitoring system, and the international community has yet to agree on the guidelines for how that system will work.

It is up to scientists and engineers to design effective monitoring systems, or strengthen existing ones. ………..

Scientists should thoroughly assess geoengineering techniques and understand what their impact on the Earth’s systems might be, including any unintended consequences. They also need to consider logistical challenges—how to actually make geoengineering techniques work, in case the world decides to use them. Then there are political and governance issues, such as how countries should respond if, say, a nation starts injecting sulfate aerosols into the atmosphere on its own to cool the planet. Despite people’s general unease with geoengineering because of its potential for major unintended consequences, it is another tool countries may eventually need to use to combat climate change. “At this point, we need to keep all options open,” Busalacchi said. “We need to have a solid and robust understanding of what geoengineering can and can’t do, in case mitigation and adaptation fall short.” https://www.scientificamerican.com/article/what-rsquo-s-next-for-climate-action/