18 March 2016, The Guardian, Welcome to the climate emergency: you’re about 20 years late February 2016 saw global warming records tumble with new data suggesting more Australians think humans are the cause. Everywhere you look right now, the Earth’s climate system seems to be breaking records. To choose the most inappropriate metaphor possible, February 2016 would have been enough to bring a lot of climate watchers out in a cold sweat. Figures from Nasa using thermometers and ocean temperature readings showed February was the hottest month on record, by quite a margin. According to satellite data, the amount of Arctic sea ice also hit an all-time low for this time of year since measurements began in 1979. Scientists also use satellite data to calculate air temperatures. Climate science contrarians and denialists like these readings because they have not shown as much warming as the more reliable readings on the surface. But February also set a new record for global temperatures from satellites. As Joe Romm at Climate Progress noted, “climate science deniers need a new meme”. These heat records have been variously described as “terrifying”, “jawdropping” and “shocking”. One climate scientist in particular, Professor Stefan Rahmstorf, appeared to capture the mood with a quote repeated in stories around the world, including here on the Guardian. “We are in a kind of climate emergency now,” said Rahmstorf, of Germany’s Potsdam Institute for Climate Impact Research. But here’s the rub. Global warming is proceeding pretty much exactly as predicted. Professor Stefan Rahmstorf. To climate scientists like Rahmstorf, the temperature records being broken right now are not a surprise and, at least according to Rahmstorf, they shouldn’t be seen as an entry point to some terrifying new era (at least not as terrifying as things already are). “The media’s view is too short-term,” he told me. “As scientists we want to keep an overview of all the data and the knowledge of how the whole system works.” Read More here
Category Archives: The Science
16 March 2016, The Conversation ,Droughts and flooding rains: it takes three oceans to explain Australia’s wild 21st-century weather. Australia is a land of extremes, and famously of “droughts and flooding rains”. That’s been truer than ever in the 21st century; since 1999 the country has see-sawed from drought to deluge with surprising speed. There was the millennium drought, which lasted more than a decade and culminated in disasters such as Victoria’s Black Saturday bushfires in 2009. Then, in 2011, Cyclone Yasi struck Queensland and a large swathe of Australia exploded under a green carpet of grasses, shrubs and trees. Filming of the movie Mad Max: Fury Road was moved from outback Australia to Namibia after the big wet of 2010-11, because Australia’s luxurious growth of wildflowers and metre-high grasses didn’t quite match the post-apocalyptic landscape the movie’s producers had in mind. In Alice Springs, the Henley-on-Todd Regatta was almost cancelled in 2011 because there was water in the normally dry river. Globally, the big wet on land caused a 5 mm drop in sea levels as large amounts of rain were deposited on Australia, South America and Africa. This coincided with an unprecedented increase in carbon stored in vegetation, especially in arid and semi-arid regions of the southern hemisphere. The greening of Australia in particular had a globally significant impact. Meteorologists have struggled to explain these wild variations in Australia’s weather. Dry years with disappointing crops have been linked to the Pacific Ocean’s El Niño phase (part of a cycle called the El Niño-Southern Oscillation (ENSO)). But despite its huge influence, not even ENSO can fully account for Australia’s extreme rainfall patterns. Our research, published this week in Nature’s Scientific Reports, offers an explanation. We found that conditions in the three oceans that surround Australia – the Pacific, Indian and Southern Oceans – combine to amplify each other’s influences on Australian weather. Read More here
14 March 2016, The Guardian, February breaks global temperature records by ‘shocking’ amount Warnings of climate emergency after surface temperatures 1.35C warmer than average temperature for the month. February smashed a century of global temperature records by “stunning” margin, according to data released by NASA. The unprecedented leap led scientists, usually wary of highlighting a single month’s temperature, to label the new record a “shocker” and warn of a “climate emergency”. The NASA data shows the average global surface temperature in February was 1.35C warmer than the average temperature for the month between 1951-1980, a far bigger margin than ever seen before. The previous record, set just one month earlier in January, was 1.15C above the long-term average for that month. “Nasa dropped a bombshell of a climate report,” said Jeff Masters and Bob Henson, who analysed the data on the Weather Underground website. “February dispensed with the one-month-old record by a full 0.21C – an extraordinary margin to beat a monthly world temperature record by.” “This result is a true shocker, and yet another reminder of the incessant long-term rise in global temperature resulting from human-produced greenhouse gases,” said Masters and Henson. “We are now hurtling at a frightening pace toward the globally agreed maximum of 2C warming over pre-industrial levels.” Read More here
14 March 2016, The Conversation, Tipping point: how we predict when Antarctica’s melting ice sheets will flood the seas. Antarctica is already feeling the heat of climate change, with rapid melting and retreat of glaciers over recent decades. Ice mass loss from Antarctica and Greenland contributes about 20% to the current rate of global sea level rise. This ice loss is projected to increase over the coming century. A recent article on The Conversation raised the concept of “climate tipping points”: thresholds in the climate system that, once breached, lead to substantial and irreversible change. Such a climate tipping point may occur as a result of the increasingly rapid decline of the Antarctic ice sheets, leading to a rapid rise in sea levels. But what is this threshold? And when will we reach it? What does the tipping point look like? The Antarctic ice sheet is a large mass of ice, up to 4 km thick in some places, and is grounded on bedrock. Ice generally flows from the interior of the continent towards the margins, speeding up as it goes. Where the ice sheet meets the ocean, large sections of connected ice – ice shelves – begin to float. These eventually melt from the base or calve off as icebergs. The whole sheet is replenished by accumulating snowfall. Floating ice shelves act like a cork in a wine bottle, slowing down the ice sheet as it flows towards the oceans. If ice shelves are removed from the system, the ice sheet will rapidly accelerate towards the ocean, bringing about further ice mass loss. A tipping point occurs if too much of the ice shelf is lost. In some glaciers, this may spark irreversible retreat. Read More here