924. Earth in Overdrive: The Rapid Climate Change of 2011-2020

With only 10 days left in the year, it is time to take a fresh look at what has been done so far. The World Meteorological Organization has also released a report on climate challenges for the decade to 2020, The Global Climate 2011-2020: A Decade of Acceleration, sounding the alarm once again about the reality of climate change. The report is a wake-up call to the reality of climate change, describing the magnitude of changes in temperature rise, melting glaciers and ice sheets, warming and acidifying oceans, and increasing greenhouse gas emissions.

The warmest decade on record

The 2011-2020 period was the warmest compared to any other consecutive decade since 1990. Many countries experienced record-high temperatures, particularly in 2016 and 2020, when strong El Niño events occurred and the highest temperatures on record were recorded. In the Arctic, where serious temperature increases are feared, the average temperature over the past decade was more than 2°C higher than the 1981-2010 average.

A decade of glacier and ice sheet loss and accelerated sea level rise

Glaciers have disappeared at an average rate of 1 meter per year. Global warming has caused snowfall to melt rather than accumulate, and glaciers that are not compensated for are only shrinking. It is estimated that all glaciers in the equatorial regions of Papua Indonesia will disappear within the next decade, the Rwenzori Mountains and Mount Kenya in Africa by 2030, and Mount Kilimanjaro by 2040. The Greenland and Antarctic ice sheets are also melting. Compared to the previous 10 years, ice sheet loss in this decade is estimated to be about 75% greater, and there are concerns about the loss of freshwater resources. Sea levels have also been rising, reportedly by 4.5 mm per year.

A decade of ocean warming and acidification

The rate of ocean warming at a depth of 2,000 meters reached a record high in 2020, and water temperatures continue to rise. In addition, CO2 is accumulating in the ocean, and the effects of oxidation are making it impossible for marine organisms to build their shells and skeletons.

A decade of rising atmospheric greenhouse gases

CO2 concentrations have been rising steadily, averaging 361.7 ppm during the decade 1991-2000, 380.3 ppm since 2001, and 402.0 ppm since 2011. The concentration of greenhouse gases in the atmosphere, which remained constant at about 280 ppm for 10,000 years before the industrial revolution, will increase by 50% to 413.2 ppm in 2020. The concentration of methane gas, which was 730 ppb (ppb = parts per billion) until the Industrial Revolution, averaged 1761.4 ppb in the decade 1991-2000, 1792.5 ppb after 2001, and 1850.2 ppb after 2011, and has been rising steadily. Greenhouse gas emissions are primarily caused by the burning of fossil fuels, deforestation, and land-use change, and are unlikely to be halted until significant reductions can be demonstrated.

Finally, the report noted the restoration of the ozone layer and the introduction of early warning systems, which have reduced the number of deaths and injuries from extreme events, but reiterated the need for further efforts and investments to combat climate change in the coming years.

Reference
WMO. The Global Climate 2011-2020, A decade of accelerating climate change, WMO-No. 1338 https://library.wmo.int/records/item/68585-the-global-climate-2011-2020

Contributors: Solongo TUMUR and IIYAMA Miyuki (Information Program)