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Greenhouse gas ‘hangover’ could last 1000s of years

‘We need to put the impact that humans have on this planet into a historic and geologic context’

mlo_full_record-800x447By Summit Voice

FRISCO — Most climate projections focus on the on the next 100 years or so, a scale of time that’s comprehensible in the context of a human life, but this generation’s production of heat-trapping greenhouse gases is likely to have impacts far beyond that horizon.

“Politicians may think in four-year terms but we as scientists can and should think in much longer terms,” said Richard Zeebe, a professor of oceanography at the University of Hawai’i. “We need to put the impact that humans have on this planet into a historic and geologic context,” said Zeebe, who recently published a study in the Proceedings of the National Academy of Sciences that examines mankind’s long-term legacy of fossil fuel burning.

Insights from climate-change episodes in the geologic past suggest that future warming from today’s greenhouse gases could be more intense and longer-lasting than previously thought. Continue reading

Climate: Parts of the tropical Pacific Ocean are shifting toward a permanent El Niño-like pattern

Archived ocean observations help create new data set for climate models

Atmospheric circulation patterns drive convection in the tropics and can have a far-reaching effect on global climate. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — A new set of more complete sea surface temperature data has helped scientists explain a gradual, decades-long slowdown of a key tropical atmospheric circulation, linking it with the steady increase in global temperatures during the past few decades.

“Our experiments show that the main driver of the change in the Walker circulation is the gradual change that has taken place in the surface temperature pattern toward a more El Niño-like state,” said Hiroki Tokinaga, associate researcher at the International Pacific Research Center, University of Hawaii at Manoa. “We don’t have enough data yet to say to what degree the slowdown over the last 60 years is due to a rise in man-made greenhouse gases or to natural cycles in the climate,” Tokinaga said.

The Walker circulation determines much of the tropical Indo-Pacific climate and has a global impact as seen in the floods and droughts spawned by the El Niño-Southern Oscillation. Meteorological observations over the last 60 years show this atmospheric circulation has slowed: the trade winds have weakened and rainfall has shifted eastward toward the central Pacific. Continue reading

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Global warming: Rate of ocean acidification far exceeds natural range of variability; coral reefs will take big hit

Yellow tangs swim in a coral reef ecoystem. PHOTO BY DWAYNE MEADOWS/NOAA.

Suitable coral reef habitat could shrink by a factor of 10

By Summit Voice

SUMMIT COUNTY — In some of the world’s oceans, acidity is increasing at more than 100 times the natural rate, according to University of Hawaii scientists, who warned once again that these changes in ocean chemistry may significantly reduce the calcification rate of corals and mollusks.

Combining computer modeling with field observations, an international team of scientists from the International Pacific Research Center, University of Hawaii at Manoa concluded that anthropogenic CO2 emissions over the last 100 to 200 years have already raised ocean acidity far beyond the range of natural variations. The study is published in the January 22 online issue of Nature Climate Change. Continue reading

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