WASHINGTON (AP) – Man-made global warming may have started a few decades earlier than scientists previously figured, a new study suggests.
Instead of the late 1800s, a slight almost imperceptible warming can now be tracked to around the 1850 in North America, Europe and Asia, according to a new study based on coral, microscopic organisms, ice cores, cave samples, tree rings and computer simulations.
And that happened when heat-trapping gases from burning fossil fuels were tiny compared to now, which means “the speed at which the climate responds to even a small change in greenhouse gases appears to be quite fast,” said study lead author Nerilie Abram, a paleoclimate scientist at the Australian National University. The study is in Wednesday’s journal Nature.
From about 1850 to 1880, Earth probably warmed around a third of a degree Fahrenheit (about .2 degrees Celsius). Still, that pales compared to about nine-tenths of a degree (half a degree Celsius) in the last 30 years or so, Abram said.
Determining when warming started is more than just a historical question. An early heating could mean either worse future climate than previously predicted if heat trapping gases aren’t controlled or, more optimistically, faster recovery by Earth if international efforts to cut greenhouse gases succeed, Abram said.