12 major impacts of global climate change in 2020

December 11, 2020
Image: Gerd Altmann from Pixabay

The provisional State of the Global Climate 2020 report, released this week by the World Meteorological Organization for discussion and review, shows that climate change continued its relentless march in 2020, which is on track to be one of the three warmest years on record.

2011–2020 will be the warmest decade on record, with the warmest six years all being since 2015.

Ocean heat is at record levels, and more than 80% of the global ocean experienced a marine heatwave at some time this year, with widespread repercussions for marine ecosystems, already suffering from more acidic waters due to carbon dioxide absorption.

The report, based on contributions by dozens of international organisations and experts, shows how high-impact events such as extreme heat, fires and floods, as well as the record-breaking Atlantic hurricane season, affected millions of people, compounding the threats to human health, human security and economic stability posed by the COVID-19 pandemic. The final 2020 report will be published in March next year.

The provisional report contains twelve key messages:

Greenhouse gases. Concentrations of the major greenhouse gases, Carbon Dioxide, Methane, and Nitrous Oxide, continued to rise in 2019 and 2020.

Global heating. Despite developing La Niña conditions, global mean temperature in 2020 is on course to be one of the three warmest on record. The past six years, including 2020, are likely to be the six warmest years on record.

Rising seas. Sea level has risen throughout the altimeter record, but recently, sea level has risen at a higher rate, due partly to increased melting of ice sheets in Greenland and Antarctica. Global mean sea level in 2020 was similar to that in 2019 and both are consistent with the long-term trend.

Marine heatwaves. More than 80% of the ocean area experienced at least one marine heat wave in 2020. More of the ocean experienced marine heat waves classified as “strong” (43%) rather than “moderate” (28%).

Ocean heating. Last year, ocean heat content was the highest on record, and the rate of warming over the past decade was higher than the long-term average, indicating continued uptake of heat from the radiative imbalance caused by greenhouse gases.

Arctic sea ice. In the Arctic, the annual minimum sea-ice extent was the second lowest on record and record low sea-ice extents were observed in July and October. Antarctic sea ice extent remained close to the long-term average.

Greenland ice. The Greenland ice sheet continued to lose mass. Although the surface mass balance was close to the long-term average, loss of ice due to iceberg calving was at the high end of the 40-year satellite record. About 152 gigatonnes of ice were lost from the ice sheet between September last year and August this year.

Rain and flooding. Heavy rain and extensive flooding occurred over large parts of Africa and Asia this year. Heavy rain and flooding affected much of the Sahel, the Greater Horn of Africa, the Indian subcontinent, China, Korea, Japan, and parts of south-east Asia.

Atlantic hurricanes. The north Atlantic hurricane season had its largest number of named storms on record (30 as at November 17), with a record number making landfall in the United States. The last storm of the season (to date) Iota, was also the most intense, reaching category 5.

Tropical storms. Tropical storm activity in other basins was near or below the long-term mean, although there were severe impacts.

Drought. Severe drought affected many parts of interior South America this year, with the worst-affected areas being northern Argentina, Paraguay and the western border areas of Brazil. Estimated agricultural losses were near US$3 billion in Brazil.

Climate-driven migration. Climate and weather events have triggered significant population movements and have severely affected vulnerable people on the move, including in the Pacific region and Central America.

[Abridged from Climate and Capitalism.]

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