Category Archives: Impacts Observed & Projected

PLEA Network

24 August 2015, Climate Code Red, As 2015 smashes temperature records, it’s hotter than you think. There is an El Nino in full swing which helps push average global temperatures higher, and records are being broken, but just how hot is it? For several years, we have heard that global warming has pushed temperatures higher by around 0.8 to 0.85 degrees Celsius (°C). But in 2015, that number is not even close. Even before this year’s strong El Nino developed, 2015 was a hot year. The first few months of the year broken records for the hottest corresponding period in previous years all the way back to the start of the instrumental record in 1880. Each month, new records fell. 

With the July data in, the US Government’s National Oceanic and Atmospheric Administration reported that July was the hottest month among the 1627 months on record since 1880, and the first seven months of the year was the hottest January-July on record: The July average temperature across global land and ocean surfaces was 0.81°C above the 20th century average. As July is climatologically the warmest month for the year, this was also the all-time highest monthly temperature in the 1880-2015 record, at 16.61°C, surpassing the previous record set in 1998 by 0.08°C. The July globally-averaged sea surface temperature was 0.75°C above the 20th century average. This was the highest temperature for any month in the 1880-2015 record, surpassing the previous record set in July 2014 by 0.07°C. The global value was driven by record warmth across large expanses of the Pacific and Indian Oceans. The year-to-date temperature combined across global land and ocean surfaces was 0.85°C above the 20th century average. This was the highest for January-July in the 1880-2015 record, surpassing the previous record set in 2010 by 0.09°C. As 2015 smashes temperature records, it’s hotter than you think. Read More here

PLEA Network

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

PLEA Network

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

PLEA Network

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