Back to this neglected blog ! Picking up the comments from Sanjay on the 22 tipping points in the global climate system, I first heard this in a lecture at the Australian Academy of Science Shine Dome covering more on climate feedback loops. So many of our computer modelling of the indicators of change have been underestimating the increasing speed of events.
Here are just a few of the tipping points that are going exponential, ocean acidity, Arctic sea ice losses, another Antarctic Ice Shelf, the Wilkins starts fracturing, very high levels of methane bubbling from the bottom of the Arctic Ocean, and more evidence of the melting of the permafrostFrom a story in The Independent by the Environment Editor Geoffrey Lean, the latest research is that the ability of the oceans to absorb CO2 is considerably diminished for geological time
Greenhouse gases will heat up the planet ‘for ever’ -
Global warming is for ever, some of the world’s top climate scientists have concluded. Their research shows that carbon dioxide emitted from today’s homes, cars and factories will continue to heat up the planet for hundreds of thousands of years……
It comes as a shock because most governments, and even many scientists, have assumed that carbon dioxide emissions would work their way out of the atmosphere in about a century, enabling it to clean itself fairly rapidly once the world switched to clean sources of energy.
But one of the main researchers – Professor David Archer of Chicago University – warns that “the climatic impacts of releasing fossil fuel carbon dioxide into the atmosphere will last longer than Stonehenge, longer than time capsules, far longer than the age of human civilisation so far. Ultimate recovery takes place on timescales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste.”
Carbon dioxide mainly leaves the atmosphere by being soaked up by the oceans, but Professor Archer says that “the pervasive notion in the climate science community and in the public at large” that this happens relatively quickly is no longer valid. He and other leading scientists spell out why in a paper to be published in the journal Annual Reviews of Earth and Planetary Sciences.
“The ocean is getting fed up with absorbing our CO2,” he says. The surface waters, about 100 metres deep, which used to sop up the gas quite fast, are now getting saturated with it – turning acid in the process – and so decreasing their uptake. They need to be replaced with fresh water from deep down, but this overturning circulation “takes centuries or a millennium”. And global warming is expected to slow this down: the hotter the surface layer becomes, the longer the replenishment takes.
Rapid melting of the Arctic ice cap is getting climate scientists very very concerned Climate change gathers steam, say scientists,
“What has us puzzled is that the changes are even faster than we would have thought possible,” said Mark Serreze of the National Snow and Ice Data Center in Boulder, Colorado.
In 2008 there was an “exponential growth” in atmospheric methane, most likely from the Arctic and sub-Arctic regions where temperature is rising rapidly.
Moving to the Himalays, tropical glaciologist, Professor Lonnie Thompson of Ohio State University featured in this story at the ABC Science (Australian Broadcasting Corporation) Tibetan glaciers rapidly melting
“At the highest elevations, we’re seeing something like an average of 0.3°C warming per decade,” says Thompson. “The Intergovernmental Panel on Climate Change projects 3°C of warming by 2100. But that’s at the surface; up at the elevations where these glaciers are there could be almost twice as much, almost 6°C.”
“I have not seen much as compelling as this to demonstrate how some glaciers are just being decapitated,” says Associate Professor Shawn Marshall of the University of Calgary.
Marshall, who studies glaciers in North America, says it’s striking how much worse glaciers near the equator are than those in the Canadian Rocky and Cascade mountain ranges.
Water supply
The finding has ominous implications for the hundreds of millions of people who depend on the waters of the Naimona’nyi and other glaciers for their livelihoods. Across the region, no one know just how much water the Himalayas have left, but Thompson says it’s dwindling fast.
“You can think of glaciers kind of like water towers,” he says. “They collect water from the monsoon in the wet season, and release it in the dry season. But how effective they are depends on how much water is in the towers.”
While looking down at Antarctica, the European Space Agency announced that scientists have identified new rifts are showing in the Wilkins Ice Shelf which will contribute to it’s break up.
Finally The Guardian carried a story in the last week about Unexpected rise in carbon-fuelled ocen acidity threatens shellfish, say scientists
Oceans absorb about a third of the carbon dioxide released into the atmosphere by human activities. When the gas dissolves in water, it forms carbonic acid, which alters the ocean’s delicate chemical balance.
Timothy Wootton, a biologist at the University of Chicago, led a team of researchers who analysed the acidity, salinity and temperature of water around Tatoosh Island off the northwestern coast of Washington state.
Over eight years, the pH level of the water fell by 0.36 to about 8.1, more than 23 times more than the predicted fall of just 0.015 points. Water is neutral if its pH is seven, and becomes more acidic as the pH falls below that.
Writing in the US journal Proceedings of the National Academy of Sciences, the scientists raise concerns at how rapidly the process is happening and the impact it could have. “Acidification may be a more urgent issue than previously predicted, at least in some areas of the ocean,” the authors write.
Last month, researchers warned that a new global deal on climate change would come too late to save many of the world’s corals. A report from the Carnegie Institution at Stanford University in California found that carbon dioxide emissions are likely to acidify seawater enough to cause widespread damage to major reefs, including the Great Barrier Reef in Australia. Even stringent cuts designed to stabilise greenhouse gas levels still put more than 90% of the world’s reefs in jeopardy.
“Declines in seawater pH were expected to happen very slowly, so we’ve been lax in dealing with the problem, but our study shows ocean acidification may be happening much quicker,” said Wootton.
