Geneva: The UN weather agency is warning of “fundamental change” afoot in the global climate and continued warming, accompanied recently by unusually high rainfall in parts of the US and Europe.
The World Meteorological Organisation (WMO) was pointing today to data released by Nasa a day earlier showing that this May was the hottest on record, and the Northern Hemisphere spring has been the hottest spring ever.
WMO global climate director Dr. David Carlson said the new data showed 370 straight months of warm or warmer-than-average temperatures worldwide. WMO said the recent El Nino was only partly to blame for the recent temperature rise.
The agency noted that heat has been particularly high in the Arctic, and has caused an early onset of the annual melting of Arctic sea ice.
In 50 years, summers across most of the globe could be hotter than any experienced to date if greenhouse gas emissions and climate change continues on its current trajectory, another new study by scientists at the US National Centre for Atmospheric Research (NCAR) has warned.
The probability that summers between 2061 and 2080 will be warmer than the hottest on record stands at 80 per cent across the world’s land areas, excluding Antarctica, which was not studied, according to the NCAR scientists. If greenhouse gas emissions are reduced, however, that probability drops to 41 per cent.
“Extremely hot summers always pose a challenge to society,” said NCAR scientist Flavio Lehner, lead author of the study.
“They can increase the risk for health issues, and can also damage crops and deepen droughts. Such summers are a true test of our adaptability to rising temperatures,” Lehner said.
The researchers used two existing sets of model simulations to study what future summers might look like.
They created both by running the NCAR-based Community Earth System Model 15 times, with one simulation assuming that greenhouse gas emissions remain unabated and the other assuming that society reduces emissions.
By using simulations created by running the same model multiple times, with only tiny differences in the initial starting conditions, the scientists could examine the range of expected summertime temperatures for future scenarios.
The researchers compared results to summertime temperatures recorded between 1920 and 2014 and to 15 sets of simulated summertime temperatures for the same period.
The results show that between 2061 and 2080, summers in large parts of North and South America, central Europe, Asia, and Africa have over 90 per cent chance of being warmer than any summer recorded if emissions continue unabated.
Reducing emissions would lower the probability but would not result in uniform benefits.