Climate change is accelerating at a rate not seen in 1,000 years, according to new findings.
By the year 2020, global temperatures could be rising by nearly half a degree per decade, over twice the rate seen over the last 900 years, climatologists warn.
Over two dozen climate models were examined, with data arranged in 40-year cycles. This is roughly the length of time houses and roads tend to exist, before being replaced.
Human activity is releasing vast quantities of carbon into the atmosphere, leading to climate change, including global warming, researchers warn. Although the long-term effects of carbon on the environment can be simulated in computer models, short-term variations in weather make short-term predictions difficult.
A base rate of global heating was determined for the period of 1850 to 1930, when human emissions of atmospheric carbon were much lower than in later decades. Tree rings, ice cores and corals were examined, in order to create a record over global temperatures, stretching over the last 2,000 years. Investigators found that temperatures rarely rose more than 0.18 degrees Fahrenheit each decade, prior to the start of the 20th Century. A similar rise would likely have taken place in the first half of the 21st Century, were it not for the influence of human activity, researchers stated.
Calculations using the extensive database predict that global temperatures will rise by around 0.45 degrees Fahrenheit every 10 years over the coming decades.
Climate models showed global temperatures rising in the future, even given the lowest likely rates of carbon emission to the atmosphere. When higher estimates were used as inputs in the model, the effect of the carbon were greater than when lower levels were utilized. Nearly every area around the world is predicted to experience rising temperatures far beyond natural fluctuations, the models predict. Those changes are expected to accelerate over time, according to researchers.
This study could show how people will need to adapt to rising global temperatures in the short term, even within the lifetimes of those on Earth today.
"In these climate model simulations, the world is just now starting to enter into a new place, where rates of temperature change are consistently larger than historical values over 40-year time spans. We need to better understand what the effects of this will be and how to prepare for them," Steve Smith from the Pacific Northwest National Laboratory, managed by the Department of Energy, said.
Predictions of global warming trends over the next few decades was profiled in the journal Nature Climate Change.
Photo: Tim J. Keegan | Flickr
