Rates of change in Earth’s surface temperature unprecedented for at least the past 1,000 years – ‘There’s not going to be anything close to equilibrium’Posted by Jim at Wednesday, March 11, 2015
By James Sullivan
10 March 2015
(Science Recorder) – According to a new paper published Monday in Nature Climate Change, it’s about to get a whole lot hotter – that’s the projected trend after looking at the weather over 40-year periods. While the fact that next century may bring us temperatures over the two degree Celsius mark (that’s 33.5 degrees Fahrenheit) sounds alarming enough, imagine a milennium of record temperatures, that could bring about the detriment of human survival.
According to the latest research, the Arctic, along with North America and Europe will be among the first regions on Earth whose climates will significantly reshape – with wet areas becoming much wetter and dry areas desiccating further. Therefore, it is imperative that policy makers and researchers begin planning for adaptations to this new environment.
“Essentially the world is entering a new regime where what is normal is going to continue to change and it’s changing at a rate than natural processes might not be able to keep up with,” said Steven Smith, a researcher at the Pacific Northwest National Laboratory.
Although an analysis of the past millennium shows a fluctuation of temperatures at 0.2°F each decade – both moving up and down, the last four decades show something rather alarming. Not only have temperatures climbed consistently each decade since 1975, the warming is encroaching on an average of 0.4°F per decade. It’s a rate that’s only barely within historical trends. By 2020, researchers expect these warming rates to accelerate beyond the historical bounds of the last 1,000 years — continuing to rise. If nations do not work to control greenhouse gas emissions, this rate is expected to spike up to 0.7°F per decade, a high that is expected to remain until at least 2100.
These historic levels of warming are expected to begin in the northern hemisphere, which is already seeing a significant decrease in ice levels. Temperatures in the Arctic are expected to rise 1.1°F per decade by the year 2040, while the warming rates in North America and Europe will be somewhat lower, the rates of warming will be equally unprecedented.
“With those high rates of change, there’s not going to be anything close to equilibrium,” said Smith. [more]
ABSTRACT: Anthropogenically driven climate changes, which are expected to impact human and natural systems, are often expressed in terms of global-mean temperature1. The rate of climate change over multi-decadal scales is also important, with faster rates of change resulting in less time for human and natural systems to adapt2. We find that present trends in greenhouse-gas and aerosol emissions are now moving the Earth system into a regime in terms of multi-decadal rates of change that are unprecedented for at least the past 1,000 years. The rate of global-mean temperature increase in the CMIP5 (ref. 3) archive over 40-year periods increases to 0.25 ± 0.05 °C (1σ) per decade by 2020, an average greater than peak rates of change during the previous one to two millennia. Regional rates of change in Europe, North America and the Arctic are higher than the global average. Research on the impacts of such near-term rates of change is urgently needed.