The report also assesses research into the projected future impact of climate change. Findings are that:
Sunday, March 30, 2014
IPCC report finds world might be irreversibly changed
The report also assesses research into the projected future impact of climate change. Findings are that:
Saturday, March 22, 2014
New IPCC climate report predicts significant threats to Australia
Tuesday, March 18, 2014
Climate change is putting world at risk of irreversible changes, scientists warn
AAAS makes rare policy intervention urging US to act swiftly to reduce carbon emissions and lower risks of climate catastrophe
Suzanne Goldenberg
The Guardian, Tuesday 18 March 2014
The world is at growing risk of "abrupt, unpredictable and potentially irreversible changes" because of a warming climate, America's premier scientific society warned on Tuesday.
In a rare intervention into a policy debate, the American Association for the Advancement of Science urged Americans to act swiftly to reduce greenhouse gas emissions – and lower the risks of leaving a climate catastrophe for future generations.
"As scientists, it is not our role to tell people what they should do," the AAAS said in a new report, What we know.
"But we consider it our responsibility as professionals to ensure, to the best of our ability, that people understand what we know: human-caused climate change is happening, we face risks of abrupt, unpredictable and potentially irreversible changes, and responding now will lower the risks and costs of taking action."
The United Nations' climate science panel, the IPCC, will gather in Yokohama, Japan next week to release the second in a series of blockbuster reports, this time outlining how a changing climate is affecting rainfall and heat waves, sea level and the oceans, fisheries and food security.But the AAAS scientists said they were releasing their own assessment ahead of time because they were concerned that Americans still failed to appreciate the gravity of climate change.
Despite "overwhelming evidence", the AAAS said Americans had failed to appreciate the seriousness of the risks posed by climate change, and had yet to mobilise at a pace and scale needed to avoid a climate catastrophe.
The scientists said they were hoping to persuade Americans to look at climate change as an issue of risk management. The society said it plans to send out scientists on speaking tours to try to begin a debate on managing those risks.
The report noted the climate is warming at almost unprecedented pace.
"The rate of climate change now may be as fast as any extended warming period over the past 65 million years, and it is projected to accelerate in the coming decades,"
An 8F rise – among the most likely scenarios could make once rare extreme weather events – 100-year floods, droughts and heat waves – almost annual occurrences, the scientists said.
Other sudden systemic changes could lie ahead – such as large scale collapse of the Antarctic and Greenland ice sheets, collapse of part of the Gulf Stream, loss of the Amazon rain forest, die-off of coral reefs, and mass extinctions.
"There is a risk of abrupt, unpredictable and potentially irreversible changes in the earth's climate system with massively disruptive impacts," the report said.
The risks of such catastrophes would only grow over time – unless there was action to cut emissions, the scientists said.
"The sooner we make a concerted effort to curtail the burning of fossil fuels as our primary energy source and releasing the C02 to the air, the lower our risk and cost will be."
Sunday, March 9, 2014
Climate action call as 'another angry summer' breaks 156 heat records
Climate Council says the summer was 'another example of climate change tearing through the record books'
Oliver Milman
The Guardian, Monday 10 March 2014
More than 150 temperature records were broken in Australia during "another angry summer" that highlighted the need for deep reductions in greenhouse gases, a new report has said.
The analysis, by the Climate Council, found that Sydney experienced its driest summer in 27 years, while Melbourne sweltered through its hottest ever 24-hour period, averaging 35.5C. The Victorian capital also had four days in a row above 41C.
Elsewhere, Adelaide had a record of 11 days at 42C or hotter during the summer, while Perth had its second hottest summer on record.
Perhaps unsurprisingly given that 79% of Queensland is now considered to be in drought, the Climate Council findings showed it was the driest summer on record for 45 locations in the state.
In New South Wales, where more than half of the state is in the grip of drought, 38 locations had their driest ever summer.
The highest temperature recorded in the summer was 49.2C in Emu Creek, Western Australia. Overall, 156 temperature records were broken in the 90 days of summer.
Eight of the hottest summers on record have occurred in the past 15 years, the council's report showed. It states it is "virtually certain" that extreme hot weather will become even more frequent and severe in Australia in the coming decades.
Rising temperatures driven by the release of heat-trapping carbon dioxide place Australians at increased risk from extreme weather events, including heatwaves, drought and bushfires, the report stated.
The summer heat followed what was Australia's hottest ever year on record in 2013.
"The latest summer was an another example of climate change tearing through the record books," said the Climate Council's Tim Flannery. "It's not just about one summer but an overall trend to more extreme weather.
"Things are getting bad and if we want to stop them getting worse this is the critical decade for action. We need to cut the emission of greenhouse gases and we need to do it urgently."
Arctic melt speeding up
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http://www.climatenewsnetwork.net/2014/03/arctic-melt-speeding-up/
By Tim Radford
It's long been established that Arctic ice is on the retreat but it's the pace of change that's surprising scientists: latest studies show the region is at its warmest for 40,000 years.
LONDON, 9 March - Ice in the Arctic continues to retreat. The season without ice is getting longer by an average of five days every 10 years, according to a new study in Geophysical Research Letters. And in some regions of the Arctic, the autumn freeze is now up to 11 days later every decade.
This means that a greater proportion of the polar region for a longer timespan no longer reflects sunlight but absorbs it. This change in albedo – the scientist's term for a planet's reflectivity – means that open sea absorbs radiation, stays warmer, and freezes again ever later.
Warming accelerates
None of this is news: sea ice in the Arctic has been both retreating and thinning in volume for four decades. Researchers have tracked the retreat of the snow line to find tiny plants exposed that had been frozen over 40,000 years ago: the implication is that the Arctic is warmer now than it has been for 40 millennia.
This warming threatens the animals that depend for their existence on a stable cycle of seasons and is accelerating at such a rate that the polar ocean could be entirely free of ice in late summer in the next four decades.
So Julienne Stroeve, of University College London and her colleagues have provided yet further confirmation of an increasing rate of change in the region in their latest study.
The scientists examined satellite imagery of the Arctic for the last 30 years, on 25 square kilometer grid, to work out the albedo of each square for every month they had data.
Their headline figure of five days is an average: in fact the pattern of freeze and thaw in the Arctic varies. In one region the melt season has been extended by 13 days, in another the melt season is actually getting shorter.
Energy increases
This increasing exposure to summer sunlight means that ever greater quantities of energy are being absorbed: several times the energy of the atomic bomb dropped on Hiroshima hits every square kilometer of the open Arctic Ocean.
"The extent of sea ice in the Arctic has been declining for the last four decades," said Professor Stroeve, "and the timing of when melt begins and ends has a large impact on the amount of ice lost each summer.
With the Arctic region becoming more accessible for longer periods of time, there is a growing need for improved prediction of when the ice retreats and reforms in the water." - Climate News Network