22 May 2017, Washington Post, Stop hoping we can fix climate change by pulling carbon out of the air, scientists warn. Scientists are expressing increasing skepticism that we’re going to be able to get out of the climate change mess by relying on a variety of large-scale land-use and technical solutions that have been not only proposed but often relied upon in scientific calculations. Two papers published last week debunk the idea of planting large volumes of trees to pull carbon dioxide out of the air — saying there just isn’t enough land available to pull it off — and also various other strategies for “carbon dioxide removal,” some of which also include massive tree plantings combined with burning their biomass and storing it below the ground. “Biomass plantations are always seen as a green kind of climate engineering because, you know, everybody likes trees,” said Lena Boysen, a climate researcher at the Max Planck Institute for Meteorology in Germany, who led one of the new studies while a researcher at the Potsdam Institute for Climate Impact Research. “But we just want to show that that’s not the complete story. They cannot do that much.” Forests have long been recognized as one of the world’s most important natural carbon sinks, capable of storing large amounts of carbon that would otherwise end up in the atmosphere. Simply preserving the world’s forest resources — and replanting areas that have already been deforested — is viewed as an important step in protecting the climate. But for years, scientists have discussed the idea of going further by using large plantations full of fast-growing, carbon-storing trees to pull extra carbon emissions out of the atmosphere, a strategy sometimes called “afforestation.” But the amount of land and other resources this strategy would require to actually help us meet our global climate goals — namely, keeping global temperatures within at least two degrees of their pre-industrial levels — is completely impractical, according to Boysen’s new study in the journal Earth’s Future, and would require the destruction of huge amounts of natural ecosystems or productive agricultural land. Read More here
Tag Archives: geoengineering
27 March 2017, The Guardian, Trump presidency ‘opens door’ to planet-hacking geoengineer experiments. As geoengineer advocates enter Trump administration, plans advance to spray sun-reflecting chemicals into atmosphere. Harvard engineers who launched the world’s biggest solar geoengineering research program may get a dangerous boost from Donald Trump, environmental organizations are warning. Under the Trump administration, enthusiasm appears to be growing for the controversial technology of solar geo-engineering, which aims to spray sulphate particles into the atmosphere to reflect the sun’s radiation back to space and decrease the temperature of Earth. Sometime in 2018, Harvard engineers David Keith and Frank Keutsch hope to test spraying from a high-altitude balloon over Arizona, in order to assess the risks and benefits of deployment on a larger scale. Keith cancelled a similar planned experiment in New Mexico in 2012, but announced he was ready for field testing at a geoengineering forum in Washington on Friday. “The context for discussing solar geoengineering research has changed substantially since we planned and funded this forum nearly one year ago,” a forum briefing paper noted. While geoengineering received little favour under Obama, high-level officials within the Trump administration have been long-time advocates for planetary-scale manipulation of Earth systems. David Schnare, an architect of Trump’s Environmental Protection Agency transition, has lobbied the US government and testified to Senate in favour of federal support for geoengineering. He has called for a multi-phase plan to fund research and conduct real-world testing within 18 months, deploy massive stratospheric spraying three years after, and continue spraying for a century, a duration geoengineers believe would be necessary to dial back the planet’s temperature. Geoengineers argue that such methods would be an inexpensive way to reduce global warming, but scientists have warned it could have catastrophic consequences for the Earth’s weather systems. Scientific modelling has shown that stratospheric spraying could drastically curtail rainfall throughout Asia, Africa and South America, causing severe droughts and threatening food supply for billions of people. Read More here
7 December 2016, Climate Home, UN to extend freeze on climate change geoengineering. Draft documents suggest countries will agree to further ban on large-scale climate techno-fixes, warning risks of damage to biodiversity outweigh potential benefits. Countries should resist the urge to experiment with large scale planetary geoengineering until it’s clear what the consequences of meddling with the oceans or atmosphere may be. That’s the nub of a decision expected to be taken at the UN’s biannual biodiversity summit taking place in Cancun, Mexico this week, emphasising a “precautionary approach” to such projects. With greenhouse gas emissions closing in on levels that could guarantee warming of 1.5C above pre industrial levels and an El Nino-boosted 2016 likely to be the hottest year on record, some scientists are looking to emergency measures. But the UN is sticking to a familiar line: pumping the atmosphere with tiny mirrors to deflect sunlight, boosting the uptake of CO2 in oceans by stimulating plankton growth, or burning wood and pumping the emissions underground could be a bad idea. “We’re concerned that with any initiative regarding the use of geoengineering there needs to be an assessment,” UN biodiversity chief Braulio Ferreira de Souza Dias told Climate Home. “These can have unforeseen results and spin-offs. If you capture carbon in the oceans, this is effective through all the food chains.” Even national risk assessments on individual geoengineering projects would still form an “incomplete basis for global regulation” says the latest iteration of the UN draft decision, echoing previous Convention on Biological Diversity (CBD) decisions in 2010, 2012 and 2014. “More trans-disciplinary research and sharing of knowledge among appropriate institutions is needed,” it says, citing potential impacts on ecosystems and potential ethical issues. Read More here
17 November 2016, Environmental Research Letters Research priorities for negative emissions. ABSTRACT: Carbon dioxide removal from the atmosphere (CDR)—also known as ‘negative emissions’—features prominently in most 2 °C scenarios and has been under increased scrutiny by scientists, citizens, and policymakers. Critics argue that ‘negative emission technologies’ (NETs) are insufficiently mature to rely on them for climate stabilization. Some even argue that 2 °C is no longer feasible or might have unacceptable social and environmental costs. Nonetheless, the Paris Agreement endorsed an aspirational goal of limiting global warming to even lower levels, arguing that climate impacts—especially for vulnerable nations such as small island states—will be unacceptably severe in a 2 °C world. While there are few pathways to 2 °C that do not rely on negative emissions, 1.5 °C scenarios are barely conceivable without them. Building on previous assessments of NETs, we identify some urgent research needs to provide a more complete picture for reaching ambitious climate targets, and the role that NETs can play in reaching them. Read More here