20 out of last 22 years warmest on record

The 20 warmest years on record have been in the past 22 years, with the top four in the past four years, says the World Meteorological Organisation (WMO).

Released on the eve of the UN Climate Summit in Poland, the WMO report said that 2018 was on course to be the fourth warmest year on record. This would mean that the past four years — 2015, 2016, 2017 and 2018 — are also the four warmest years in the series, 2018 being the coolest of the four.

The report shows that the global average temperature for the first 10 months of the year was nearly 1°C above the pre-industrial baseline (1850-1900). This is based on five independently maintained global temperature data sets.

The Intergovernmental Panel on Climate Change (IPCC) special report on Global Warming of 1.5°C reported that the average global temperature for the decade 2006-2015 was 0.86 degrees Celsius above the pre-industrial baseline.

The average increase above the same baseline for the most recent decade 2009-2018 was about 0.93°C and for the past five years, 2014-2018, it was 1.04°C above the pre-industrial baseline. This means the world is not on track to meet climate change targets and rein in temperature rises.

“Greenhouse gas concentrations are at record high levels and if the current trend continues, we may see temperature increase by 3-5°C by the end of the century,” WMO secretary-general Petteri Taalas said in a statement issued on November 29.

The warming in the previous four years was due to El Nino effect — an unusual warming of the Pacific Ocean that wrecks havoc with weather around the world.

The current year started with a weak La Nina event, which continued until March. By October, sea-surface temperatures in the eastern Tropical Pacific were showing signs of a return to El Nino conditions, although the atmosphere as yet has shown little response. If El Nino develops, 2019 is likely to be warmer than 2018.

The WMO statement on the state of world’s climate mentioned Kerala flood as one of the consequences of extreme climates, which would be more frequent in the years to come. Rainfall for Kerala in August was 96% above the long-term average.