18 October 2015, Climate News Network, Climate changes can kick in below 2°C limit. Sudden shifts in settled climates can occur long before global warming reaches the internationally-agreed safety level, European scientists say. Climate change could arrive with startling speed. New research has identified at least 37 “tipping points” that would serve as evidence that climate change has happened – and happened abruptly in one particular region. And 18 of them could happen even before the world warms by an average of 2°C, the proposed “safe limit” for global warming. Weather is what happens, climate is what people grow to expect from the weather. So climate change, driven by global warming as a consequence of rising carbon dioxide levels, in response to more than a century of fossil fuel combustion, could be – for many people – gradual, imperceptible and difficult to identify immediately. But Sybren Drijfhout, of the University of Southampton in the UK and his collaborators in France, the Netherlands and Germany, are not so sure. They report in the Proceedings of the National Academy of Sciences that they “screened” the massive ensemble of climate models that inform the most recent reports from the Intergovernmental Panel on Climate Change, and found evidence of abrupt regional changes in the ocean, the sea ice, the snow cover, the permafrost and in the terrestrial biosphere that could happen as average global temperatures reached a certain level. The models did not all simulate the same outcomes, but most of them did predict one or more abrupt regional shifts. No safe limit. But the future is not an exact science. “Our results show that the different state-of-the-art models agree that abrupt changes are likely, but that predicting when and where they will occur remains very difficult,” said Professor Drijfhout. “Also, our results show that no safe limit exists and that many abrupt shifts already occur for global warming levels much lower than two degrees.” The idea of a “tipping point” for climate change has been around for decades: the hypothesis is that a climate regime endures – perhaps with an increasing frequency of heat waves or windstorms or floods – as the average temperatures rise. However, at some point, there must be a dramatic shift to a new set of norms.Read More here
Tag Archives: Extreme Events
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
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
13 July 2015, Climate News Network, Record torrential rainfall linked to warming climate: Scientists show that devastating increases in extreme rainfall over the last 30 years fit in with global temperature rise caused by greenhouse gases. If you think you’re getting an unusually hard soaking more often when you go out in the rain, you’re probably right. A team of scientists in Germany says record-breaking heavy rainfall has been increasing strikingly in the last 30 years as global temperatures increase. Before 1980, they say, the explanation was fluctuations in natural variability. But since then they have detected a clear upward trend in downpours that is consistent with a warming world. The scientists, from the Potsdam Institute for Climate Impact Research (PIK), report in the journal Climatic Change that this increase is to be expected with rising global temperatures, caused by greenhouse gas emissions from burning fossil fuels. Read More here