By Stephen Leahy
Oct 26 (IPS) – Global warming has been compared to a slow-moving train wreck, in which the passengers are blissfully unaware of the coming catastrophe.
With the shocking loss of the Arctic sea ice this summer and several new reports this week that oceans and tropical forests are now absorbing less of the world’s steadily rising carbon emissions, our collective train wreck appears to have already tipped into fast forward.
“Global warming is a big feature of our lives now. It is no longer something that only future generations will have to cope with,” said Ted Scambos, senior research scientist at the National Snow and Ice Data Centre in the U.S. city of Boulder, Colorado.
The major ecosystems that absorb carbon emissions from the atmosphere are failing, and it is happening faster than anticipated, Scambos told IPS.
The concentration of carbon dioxide (CO2) in the atmosphere is increasing much more rapidly than even the surging economic growth of China and India and the global economy can account for. The reason is a decline in the efficiency of emissions-absorbing “carbon sinks” on land and in the oceans, researchers reported this week in the Proceedings of the National Academy of Science.
About half of the CO2 emissions resulting from human activities are absorbed by natural “sinks”, such as forests, other vegetation and the oceans, but this new study shows that the efficiency of these sinks has fallen significantly over the past half century.
Corinne Le Quéré, a climate researcher at the British Antarctic Survey, told IPS last May that stronger winds in the Southern Ocean caused by global warming have resulted in it absorbing less and less carbon since 1981. Those winds churn the ocean waters, bringing up more dissolved carbon dioxide from the deep sea to the surface, and consequently less carbon dioxide is absorbed from the atmosphere.
The process is also making the oceans more acidic, threatening coral and other marine life.
“We are depending on carbon sinks like the oceans to absorb a huge amount of our emissions,” Le Quéré said. “This means there is more urgency than ever to reduce our emissions.”
Oceans are also warming, which also reduces their ability to absorb carbon, said Scambos. Warmer North Pacific water is flowing into the Arctic Ocean and is one of the main reasons behind this summer’s startling loss of summer sea ice in the Arctic. For the first time in human memory, the fabled Northwest Passage from the Atlantic to the Pacific Ocean was ice-free.
While Arctic sea ice retreats temporarily every summer, this summer the retreat was 2.6 million square kilometres larger than any previous summer’s loss..
The big meltdown was outside the range of previous scientific projections, and even worst-case scenarios, said Scambos. It likely represents a new era of accelerated warming over the next few decades, he said. This acceleration may well mean that the Arctic could be completely ice-free in 10 years — decades faster than previous predications made only a year ago.
Hotter oceans are also statistically correlated with four of the five major extinctions in the past 520 million years of Earth’s history, according to a study published Wednesday in the Proceedings of the Royal Society B, a British journal focusing on biological sciences.
Earth is on track to hit this extinction-triggering warming point in about 100 years unless greenhouse gas emissions are curbed, predicts Peter Mayhew of the University of York in Britain.
Another tipping point may have already been reached as warming temperatures appear to have reduced tropical forests’ ability to absorb carbon, says a series of new studies published Thursday in the New Scientist magazine.
For complete article please click CO2 Levels Begin Accelerated Climb