Due to global warming, global climate models predict hurricanes will likely cause more intense rainfall and have an increased coastal flood risk due to higher storm surge caused by rising seas. Additionally, the global frequency of storms may decrease or remain unchanged, but hurricanes that form are more likely to become intense.
The past seven years, between 2015 to 2021, were the warmest years on record, the WMO has warned. Last year alone was between the fifth and seventh warmest year on record globally. The average temperature globally in 2021 was around 1.11C above average world temperatures between 1850 and 1900 – known as the “pre-industrial average”.
Sea levels also reached a new record high in 2021. Globally, the sea level rose 4.5mm a year on average between 2013 and 2021. In several regions, the sea level is rising “substantially faster” than the global average, the WMO says. These include the South-west Pacific, the South-west Indian Ocean and the South Atlantic.
The ozone hole over the Antarctic in 2021 was “larger and deeper” than 70% of the ozone holes measured since 1979, the WMO finds. It expanded to its widest area of the year – 24.8 million km² – during October. The WMO says it was driven by colder-than-average conditions in 2021 in the stratosphere – the second layer of the Earth’s atmosphere from ground level. A strong polar vortex – the band of cold air around the Earth’s North Pole – was another key contributing factor.
Rainfall was recorded for the first time ever at the highest point on Greenland’s ice sheet. This is Summit Station, a research station that is more than 3,200 metres above sea level.
Several hours of rain were observed at Summit Station on 14 August 2021. Air temperatures also stayed above freezing for about nine hours. This was part of an “exceptional” mid-August melt event for Greenland, linked to a mass of warm, humid air, the WMO says.
In western North America and the Mediterranean, it was “exceptional heat waves” that were breaking records, notes the State of the Global Climate 2021. Death Valley in California recorded the world’s highest-ever temperature since at least the 1930s when the temperature reached 54.4C on 9 July 2021. Italy set a new provisional European record on 11 August when a research station near Syracuse in Sicily recorded a temperature of 48.8C. Kairouan in Tunisia reached a record 50.3C. Spain and Turkey also broke new national records, with a temperature of 47.4C recorded at Montoro in southern Spain and 49.1C at Cizre near Turkey’s border with Syria.
When Hurricane Ida hit Louisiana in the United States on 29 August last year, its 240km-per-hour winds matched the strongest landfall on record for the state, the WMO says. Ida was the heaviest hurricane of the North Atlantic season, causing major wind damage and flooding from storm surges. The hurricane caused an estimated $75 billion of economic losses in the US and is blamed for 115 deaths in the US and Venezuela. There were 21 named storms in 2021, well above the average of 14 a year between 1981 and 2010, the WMO notes.
In mid-July 2021, Western Europe saw some of its worst flooding ever recorded. Western Germany and eastern Belgium were worst affected. Hagen in western Germany reported 241mm of rainfall in 22 hours. Rivers flooded, several towns were inundated and there were also landslides. Germany reported 183 deaths and Belgium, 36. The flooding is thought to have cost Germany $20 billion in economic losses. France, the Netherlands, Luxembourg and Switzerland also experienced heavy flooding.
Drought led to a new water level low for Lake Mead, a reservoir on the Colorado River in Southwestern US. In July, the reservoir fell to 47m below its full capacity, its lowest level on record. Drought also affected other parts of the world, including Iran, Pakistan, Afghanistan, Turkey and Turkmenistan. In Canada, severe drought meant predicted harvest levels for wheat and canola – a crop used to create cooking oil and animal feed – were 35% to 40% below 2020 levels.