18 August 2015, Atmospheric Chemistry and Physics, Abstract. The injection of sulfur dioxide (SO2) into the stratosphere to form an artificial stratospheric aerosol layer is discussed as an option for solar radiation management. The related reduction of radiative forcing depends upon the injected amount of sulfur dioxide, but aerosol model studies indicate a decrease in forcing efficiency with increasing injection rate. None of these studies, however, consider injection rates greater than 20 Tg(S) yr−1. But this would be necessary to counteract the strong anthropogenic forcing expected if “business as usual” emission conditions continue throughout this century. To understand the effects of the injection of larger amounts of SO2, we have calculated the effects of SO2 injections up to 100 Tg(S) yr−1. We estimate the reliability of our results through consideration of various injection strategies and from comparison with results obtained from other models. Our calculations show that the efficiency of such a geoengineering method, expressed as the ratio between sulfate aerosol forcing and injection rate, decays exponentially. This result implies that the sulfate solar radiation management strategy required to keep temperatures constant at that anticipated for 2020, while maintaining business as usual conditions, would require atmospheric injections of approximately 45 Tg(S) yr−1 (±15 % or 7 Tg(S) yr−1) at a height corresponding to 60 hPa. This emission is equivalent to 5 to 7 times the Mt. Pinatubo eruption each year. Read More here
Category Archives: Impacts Observed & Projected
17 August, Climate News Network, Andes’ migrating trees are moving towards extinction. Highland tree species in the Andes are decreasing as global warming caused by greenhouse gas emissions forces lowland varieties to move upwards into cooler climes. Scientists have known for years that, in a warming world, many living things try to move uphill to seek survival where the air is cooler. But new research provides a dire warning of the risks for those unable to move fast enough. Unlike animals, trees and other sorts of vegetation cannot move quickly to escape the heat. And for some of them, it seems, there is no survival option available. They simply die. A study published in the Proceedings of the National Academy of Sciences reports that the number of highland tree species in the Andes mountains of South America is decreasing as lowland trees move up the slope to avoid the rising temperatures and changing rainfall patterns. The results suggest that tropical tree species in the region are at risk of extinction because of the intensification of warming, caused by emissions of greenhouse gases from human activities. Can’t escape. “The effects of climate change are everywhere – you can’t escape it,” says Kenneth J. Feeley, a researcher in the Department of Biological Sciences and International Centre for Tropical Botany at Florida International University. “Some people hold the notion that the Amazon is an isolated and pristine ecosystem, immune to disturbances. We need to change our mindset and open our eyes to the fact that, even in the middle of the Amazon or the remote Andes mountains, species are at risk. Read More here
15 August, Climate News Network, Extreme weather puts Africa’s food security at risk. A British government scientific panel says increasingly frequent heat waves, droughts and other extreme weather threaten more – and more severe – global food crises. Developing countries in sub-Saharan Africa which depend heavily on food imports will be worst hit by the increasingly extreme global weather, a report says, with the Middle East and North Africa also threatened, in this case by social unrest. In contrast, the authors say the impact on the world’s biggest economies is likely to be “muted”. But they think a serious crisis could occur as soon as 2016, with repercussions in many countries. They write: “We present evidence that the global food system is vulnerable to production shocks caused by extreme weather, and that this risk is growing…preliminary analysis of limited existing data suggests that the risk of a 1-in-100 year production shock is likely to increase to 1-in-30 or more by 2040.” The report was jointly commissioned by the UK’s Foreign and Commonwealth Office and its Government Science and Innovation Network, with a foreword by the country’s former chief government scientist, Sir David King. He writes: “We know that the climate is changing and weather records are being broken all the time…The food system we increasingly rely on is a global enterprise. Up to now it’s been pretty robust and extreme weather has had limited impact on a global scale. But…the risks are serious and should be a cause for concern. Read More here
12 August 2015, University of Veterinary Medicine, Vienna, Wild boars are gaining ground – climate change boosts population growth. The wild boar population in Europe is growing. However, the reasons for this growth were not yet clear. Scientists from the Research Institute of Wildlife Ecology (FIWI) of the Vetmeduni Vienna now found that climate change plays a major role. The number of wild boars grows particularly after mild winters. Also food availability is a decisive factor. There are more wild boars after years with high beechnut yield. The research results have recently been published in the journal Plos One. The wild boar population in Europe has been constantly growing since the 1980s. This is more and more becoming a problem for agriculture when animals raid the fields, looking for feed. “It is not so easy to determine the number of wild boars in Europe,” says wildlife biologist and first author of the study, Sebastian Vetter. “Therefore we analysed data on hunting bags and road accidents involving wild boar. Doing this we were able to depict the growth of the wild boar population.” Read more here