Global temperatures for the first five months of 2018 have been the highest on record for a La Niña year, according to the US National Oceanic and Atmospheric Administration.
La Niña is the positive phase of the El Niño Southern Oscillation and is associated with cooler-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean. El Niño is the warm phase of the El Niño Southern Oscillation and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific, including off the Pacific coast of South America.
Higher temperatures lead to more frequent and long-lasting heat waves causing adverse environmental impacts. Extreme temperatures, for instance, affect human health in the form of heat strokes, heat cramps, and even death; the agricultural sector faces retarded crop growth; and the energy sector experiences difficulties coping up with the increasing use of cooling during high temperatures. Moreover, extreme weather affects water supplies, plants, animals and ecosystems, and forests.
Addressing the dangers associated with extreme weather conditions, the Executive Secretary of the UN Climate Change, Patricia Espinosa, said: “We must keep an eye on the future. As the superstorms and monsoon flooding of last year and the extreme heat and extreme cold of this year show – we still have a long way to go to deliver on the promise of the Paris Climate Change Agreement.”
May 2018 was the fourth warmest May on record, the 42nd consecutive May and the 401st consecutive month above the 20th century average. The US space agency NASA, which uses a slightly different analysis, also found that May was the fourth warmest May on record, whilst the European Centre for Medium Range Weather Forecasting Copernicus Climate Change Service ranked it as third.
This year, record warmth was observed across parts of North America, Europe and Asia, as well as the Atlantic, Pacific and Indian Oceans. Record cold May temperatures were limited to north-eastern Canada and the northern Atlantic Ocean, off the southern coast of Greenland.
Rankings of individual months – or even years – are less important than the long-term warming trend as a result of record high concentrations of greenhouse gases in the atmosphere. The year 2017 was the third warmest year on record and the warmest with an El Niño event. The year 2018 started with a weak La Niña – which tends to have a cooling effect.
The May average Arctic sea ice extent was the second smallest after 2016 in the 40-year record, 8.1 percent below the 1981-2010 average, according to an analysis by the US National Snow and Ice Data Center. This was mostly due to much-below-average sea ice in the Bering and Chukchi Seas.
Antarctic sea ice extent during May was the third smallest May extent on record, 8.6 percent below the 1981-2010 average. Ice losses from Antarctica have tripled since 2012, increasing global sea levels by 0.12 inch (3 millimeters) in that timeframe alone, according to a major new international climate assessment funded by NASA and ESA (European Space Agency).
The study published in the journal Nature showed that ice losses from Antarctica are causing sea levels to rise faster today than at any time in the past 25 years. Results of the Ice Sheet Mass Balance Inter-Comparison Exercise (IMBIE).
According to NASA, “Antarctica’s potential contribution to global sea level rise from its land-held ice is almost 7.5 times greater than all other sources of land-held ice in the world combined. The continent stores enough frozen water to raise global sea levels by 190 feet (58 meters), if it were to melt entirely. Knowing how much ice it’s losing is key to understanding the impacts of climate change now and its pace in the future.”
In addition to long-term climate change indicators, high-impact weather events also continued unabated during the first five months of the year. The start of the South-Asian monsoon season brought unusually heavy rainfall to Bangladesh, adding to the misery of hundreds of thousands of refugees.
Floods affected many other people and killed dozens in East Africa. Rare tropical cyclones hit Somalia, Djibouti, Yemen and Oman. Sand and dust storms in India killed several hundred people, whilst Pakistan suffered successive heatwaves.
Unusually high temperatures and lack of rainfall have combined to pose a risk of wildfires in Scandinavia and the Baltic region, whereas other parts of Europe such as France have seen new daily rainfall records this month.
The Caribbean is preparing for yet another hurricane season while still trying to recover from the 2017 devastating season, which was the costliest on record.