2020, another year of advantage for climate change

The relentless march of climate change did not stop in 2020, which is on track to be one of the three warmest years on record, the World Meteorological Organization said on Wednesday.

Scientists warn that the 2011-2020 decade will be the warmest in history, and since 2015 warming records have been broken every year.

The Interim State of Climate 2020 report highlights that rising temperatures are not only spreading on land, but also in the ocean, 80% of which experienced at least one heat wave in 2020. This had widespread repercussions for marine ecosystems that already suffer from more acidic waters due to the absorption of carbon dioxide (CO2).

The report, based on contributions from dozens of international organizations and experts, shows how high-impact events, including extreme heat, wildfires and floods, as well as the record Atlantic hurricane season, affected millions of people, compounding the threats to humans in terms of health and security and economic stability posed by the COVID-19 pandemic.

A year out of the ordinary

“The average global temperature in 2020 is set at about 1.2°C above the pre-industrial level (1850-1900). There is at least a 20% chance that it will temporarily exceed 1.5°C by 2024,” said WMO Secretary-General Petteri Taalas.

The Paris Agreement signed in 2015 seeks to limit warming to less than 2ºC, and scientists from the Intergovernmental Panel on Climate Change have warned that reaching 1.5ºC will already bring ecosystem catastrophes such as the disappearance of coral reefs.

Taalas explained that previous years with record heat have generally coincided with a strong El Niño episode, as was the case in 2016.

“We are now experiencing a La Niña phenomenon, which has a cooling effect on global temperatures, but it has not been enough to curb this year’s heat,” he said.

Despite the current La Niña conditions, this year has already shown near-record heat comparable to the previous record of 2016.

“2020 has been, sadly, another extraordinary year for our climate. We saw new extreme temperatures on land, at sea and especially in the Arctic. Wildfires consumed vast areas in Australia, Siberia, the U.S. West Coast and South America, sending plumes of smoke that circumnavigated the world. We saw a record number of Atlantic hurricanes, including consecutive category 4 hurricanes unprecedented in Central America in November. Floods in parts of Africa and Southeast Asia caused massive population displacement and undermined the food security of millions,” the WMO Director said.

Key report data

Temperatures:

The global average temperature from January to October 2020 was around 1.2°C above the baseline of 1850-1900, used as an approximation of pre-industrial levels. It is very likely that 2020 will be one of the three warmest years on record globally. Modern temperature records began in 1850.

The most notable heat was observed in northern Asia, particularly in the Siberian Arctic, where temperatures were more than 5°C above average. The Siberian heat culminated in late June, when it reached 38.0°C in Verkhoyansk on the 20th, the highest known temperature anywhere north of the Arctic Circle. This fueled the most active wildfire season in an 18-year data record, as estimated in terms of CO2 emissions released by the fires.

Other notable areas of warming include limited areas of the southwestern United States, parts of northern and western South America, parts of Central America, and broader areas of Eurasia, including regions of China. In Europe, the warmest January-October period on record was recorded

Sea ice

Since the mid-1980s, the Arctic has warmed at least twice as fast as the global average, reinforcing a long downward trend in arctic sea ice extent in summer, which has repercussions on the climate of mid-latitude regions.

Arctic sea ice hit its annual low in September as the second-lowest in the 42-year satellite record. Arctic sea ice in July and October 2020 was the lowest on record.

Likewise, sea ice in the Laptev Sea has been exceptionally low during spring, summer and autumn, and the Northern Sea Route was ice-free or nearly ice-free from July to October 2020.

In contrast, Antarctic ice in 2020 was close to or slightly above the 42-year average.

Greenland continued to lose ice, losing 152 gigatons this year, albeit at a slower rate than in 2019.

Sea level rise and ocean heat

Ocean heat content for 2019 was the highest recorded in datasets dating back to 1960. The report states that “there is a clear signal” of faster heat absorption in recent decades. More than 90% of the excess energy that accumulates in the climate system as a result of rising greenhouse gas concentrations goes into the ocean.

On average, since the beginning of 1993, the global average rate of sea level rise based on altimetry amounts to 3.3 ± 0.3 mm per year. The rate has also increased during that time. A greater loss of ice mass from the ice sheets is the main cause of this increase.

The average sea level worldwide in 2020 for now is similar to that of 2019 and consistent with the long-term trend. The development of La Niña conditions has led to a recent small drop in sea level, something that has also been associated with previous events of this phenomenon.

The strongest regional trends from 1993 to January 2020 are seen in the Southern Hemisphere: east of Madagascar in the Indian Ocean; east of New Zealand in the Pacific Ocean; and east of Rio de la Plata in South America in the South Atlantic.

As with onshore heat waves, extreme heat can affect the near-surface layer of the oceans with a variety of consequences for marine life and dependent communities.

Much of the ocean experienced at least one “strong” marine heat wave sometime in 2020. The Laptev Sea experienced an extreme marine heat wave from June to October.

Ocean acidification

Another threat to marine ecosystems is ocean acidification which is also increasing. The ocean absorbs about 23% of annual anthropogenic CO2 emissions from the atmosphere, helping to mitigate the impacts of climate change on the planet.

The ecological costs of this process for the ocean are high, as CO2 reacts with seawater lowering its pH; a process known as acidification. A decrease in average pH has been detected at available observation sites between 2015 and 2019. A wider variety of sources, including measurements of other variables, also show a steady increase in global ocean acidification.

This process affects many organisms and ecosystem services, and is a threat to human food systems by endangering fisheries and aquaculture. The scientists explain that a problem particularly in the polar oceans due to the ocean chemistry of these cold regions.

It also affects coastal protection by weakening coral reefs, which protect coastlines. As ocean acidity increases, so does its ability to absorb CO2 from the atmosphere, making it difficult for the ocean to moderate climate change.

Regular global observation and measurement of ocean acidification is needed to improve understanding of its consequences, enable modelling and prediction of change and variability, and help inform mitigation and adaptation strategies, the WMO report warns.

Data on high-impact events

Floods

The study highlights that severe flooding affected many millions of people in East Africa and the Sahel, South Asia, China and Vietnam.

Kenya and Sudan were the hardest hit in Africa, with 285 and 155 deaths recorded respectively. Lake Victoria reached record levels in May, the Niger and Nile rivers reached record levels in Niamey (Niger) and Khartoum (Sudan). Flooding also contributed to the ongoing dangerous locust outbreak.

In South Asia, India experienced one of the two wettest monsoon seasons since 1994, August was the wettest month on record in Pakistan, and widespread flooding was observed throughout the region (including Bangladesh, Nepal, and Myanmar).

In China, persistent heavy rains in the Yangtze River basin during the monsoon season also caused severe flooding. Reported economic losses exceeded $15 billion and at least 279 deaths were reported during that period.

In Vietnam, heavy rains typical of the arrival of the northeast monsoon were exacerbated by a succession of tropical cyclones and depressions, eight of which made landfall in less than five weeks.

Heat, drought and fires

In 2020, a severe drought affected many parts of the interior of South America, with the hardest-hit areas being northern Argentina, Paraguay, and the western border areas of Brazil. Estimated agricultural losses were close to $3 billion in Brazil alone. There was significant wildfire activity throughout the region, but it was most severe in the Pantanal wetlands in western Brazil.

In the United States, the largest fires ever recorded occurred in late summer and fall. Widespread drought and extreme heat contributed to the fires, with July to September recording the hottest, driest days in the southwest. Death Valley in California reached 54.4°C on August 16, the highest known temperature in the world in at least the last 80 years.

In the Caribbean, large heat waves occurred in April and September. Temperatures reached 39.7°C in Veguitas on April 12, a national record for Cuba, while Havana also had its hottest day at 38.5°C.

Australia broke heat records in early 2020, including the highest temperatures observed in an Australian metropolitan area, in western Sydney, when Penrith reached 48.9°C on January 4.

In the eastern Mediterranean, there were all-time records set in Jerusalem (42.7°C) and Eilat (48.9°C) on September 4, following a late July heatwave in the Middle East in which Kuwait’s airport reached 52.1°C and Baghdad 51.8°C.

Tropical cyclones and storms

The number of tropical cyclones globally was above average in 2020, with 96 cyclones as of November 17 in the 2020 Northern Hemisphere and 2019-2020 Southern Hemisphere seasons.

The North Atlantic region had an exceptionally active season, with 30 tropical cyclones as of November 17, more than double the average between 1981 and 2010, and breaking the record for a full season, set in 2005. At a time when the season is normally coming to an end, two Category 4 hurricanes made landfall in Central America in less than two weeks in November, leading to devastating flooding and many casualties.

Cyclone Amphan, which made landfall on May 20 near the India-Bangladesh border, was the costliest on record in the northern Indian Ocean, with economic losses recorded in India of about US$14 billion. Large-scale evacuations from coastal areas of India and Bangladesh helped reduce the number of casualties compared to previous cyclones in the region.

Risks and impacts of COVID-19

During the first half of 2020, approximately 10 million displacements were recorded, largely due to hydrometeorological hazards and disasters, concentrated mainly in South and Southeast Asia and the Horn of Africa. In 2020, the COVID-19 pandemic has added an additional dimension to concerns about human mobility.

According to the Food and Agriculture Organization of the United Nations and the World Food Programme, more than 50 million people have been doubly affected: by climate-related disasters (floods, droughts and storms) and the COVID-19 pandemic in 2020.

Central American countries are suffering the impact of hurricanes Eta and Iota, COVID-19 and other pre-existing humanitarian crises. The Honduran government estimated that 53,000 hectares of farmland, mainly rice, beans and sugarcane, were razed to the ground.

Lessons and opportunities to improve climate action

According to the International Monetary Fund, the current global recession caused by the COVID-19 pandemic makes it difficult to enact the policies needed for mitigation, but also presents opportunities to put the economy on a greener path in order to boost investment in green and resilient products. public infrastructure, thus supporting GDP and employment during the recovery phase.

“This year is the fifth anniversary of the Paris Agreement on Climate Change. We welcome all recent commitments by governments to reduce greenhouse gas emissions because we are currently not on the right track and more efforts are needed,” said WMO Secretary-General Petteri Talas.

The interim report on the state of the 2020 global climate is based on temperature data from January to October. The 2020 final report will be published in March 2021.

Source: UN News