Heat risks are nearly unthinkable, as global warming remains major culprit behind extreme weather

Source: Xinhua| 2017-07-18 Editor: Song Lifang

GENEVA, July 18 (Xinhua) — Global warming remains the main reason for recent extreme weather conditions worldwide, including the long-lasting heat waves and scorching temperatures across the northern hemisphere, according to a latest study of the World Meteorological Organization (WMO).

Using the climate assessment models of the Intergovernmental Panel on Climate Change, the WMO predicted that if greenhouse gas emissions continue to increase, the Earth’s average global surface temperature could rise more than 4 degrees Celsius by the end of the century, meaning more intense heat waves and more extremely hot days and nights ahead.

For illustration, the WMO and its partners have launched a TV series to show how hot the world’s major cities could become by the year 2100 if emissions remain high globally. Paris, for example, will see its average summer daily highs to rise to 29.2 degrees Celsius from 22.7 degrees.

The study, which was released this week, warned that many of the assessed cities could see their maximum daily temperatures in summer rise by as much as 6 to 9 degrees Celsius.

Though the TV programs are just possible scenarios instead of true forecasts, they are based on the most up-to-date climate science data, and they “paint a compelling picture of how climate change may affect daily life in cities where most of the world’s population lives,” said WMO Secretary-General Petteri Taalas.

The WMO also warned that extreme weather like long-lasting high temperatures and torrential summer storms could also lead to the scarcity in water and energy, problems of public health and transportation, as well as worsened air quality.

Similar conclusions come from a recent report by the Asian Development Bank (ADB) and Potsdam Institute for Climate Impact Research, which projects a 6-degree rise of average temperature on the Asian continent by the end of this century if global warming is not curbed. In parts of Tajikistan, Afghanistan and Pakistan, the average rise could be up to 8 degrees Celsius.

“The global climate crisis are arguably the biggest challenge human civilization faces in the 21st century, with the Asia and Pacific region at the heart of it all,” said ADB Vice President Bambang Susantono.

“Countries in Asia and the Pacific are at the highest risk of plummeting into deeper poverty — and disaster — if (climate change) mitigation and adaptation efforts are not quickly and strongly implemented.”

Despite speculations that the recent extreme weather conditions had links to El Nino effects, the WMO clarified in early July that it was not. Statistics from the UN agency show that since late April, sea surface temperature anomalies in the east-central equatorial Pacific have risen by almost 0.5 degree Celsius, approaching the threshold of El Nino conditions. However, atmospheric patterns have continued to reflect neutral El Nino-Southern Oscillation (ENSO) conditions.

Judging from most dynamical models surveyed, the WMO predicts that these slightly above-average but still ENSO-neutral conditions are to persist until the end of 2017. The agency gives a 50-60 percent probability of ENSO-neutral state in the second half of 2017, and a somewhat lower likelihood, at around 35-45 percent, of El Nino, while La Nina, the cold phase of ENSO, stands very little chance of developing.

“Even without a strong El Nino in 2017, we are seeing other remarkable changes across the planet that are challenging the limits of our understanding of the climate system. We are now in truly uncharted territory,” said World Climate Research Program Director David Carlson.