Counterintuitively, colder winters are an indicator of global warming. Skeptics argued that harsher winters are the irrefutable proof that climate change is a bogus claim. However, a new research underlines the fact that climate is a complex system. Processes taking place in various parts of the world are interdependent.
Tokyo University and the Japanese National Institute of Polar Research ran the most complex computer simulation to date on the matter. According to the results, colder winters are the results of disappearing Arctic sea ice.
After the sea ice melts, the exposed water absorbs heat. The water warms the air above it and the whole process slows down the circulation of air currents. The “blocking pattern” pulls the cold air over Europe and northern Asia and rests there for longer periods.
“Both reanalysis data and our simulations suggest that sea-ice decline leads to more frequent Eurasian blocking situations, which in turn favour cold-air advection to Eurasia and hence severe winters,” the authors say in the study published in Nature Geoscience.
There is one solid proof backing the theory, the Japanese researchers claim. Colder winters in the last decades and lower levels of Arctic sea ice are associated. Researchers warn that we will enjoy colder winters for other several decades. Afterwards, the Arctic ice cap is expected to melt completely. The event may take place in the 2030s. Consequently, the average temperatures are expected to rise.
Global warming changes the climate according to its own rules and processes. Extreme weather is a sign of change, whether it manifests through extended heat waves or frost periods, researchers point out. Unfortunately, the episodes of extreme weather in the last decades are not a sign of normal variation, as some researchers previously believed.
Prof Colin Summerhayes at the Scott Polar Research Institute reiterates the message. He told Nature Geoscience that “[t]his counterintuitive effect of the global warming that led to the sea ice decline in the first place makes some people think that global warming has stopped. It has not. Although average surface warming has been slower since 2000, the Arctic has gone on warming rapidly throughout this time.”
Recent data from the National Oceanic and Atmospheric Administration for September suggests that 2014 is on track to be the hottest year on record. Temperatures are recorded since 1880 and the 10 warmest years have been registered after 2000.