State of global climate in 2021 – WMO provisioanl report

State of Climate in 2021

Geneva, 31 October 2021 (WMO) – Record atmospheric greenhouse gas concentrations and associated accumulated heat have propelled the planet into uncharted territory, with far-reaching repercussions for current and future generations, according to the World Meteorological Organization (WMO).

The past seven years are on track to be the seven warmest on record, according to the provisional WMO State of the Global Climate 2021 report, based on data for the first nine months of 2021. A temporary cooling “La Niña” event early in the year means that 2021 is expected to be “only” the fifth to seventh warmest year on record. But this does not negate or reverse the long-term trend of rising temperatures.The report combines input from multiple United Nations agencies, national meteorological and hydrological services and scientific experts. It highlights impacts on food security and population displacement, harming crucial ecosystems and undermining progress towards the Sustainable Development Goals. It was released at a press conference on the opening day of COP26.

Global sea level rise accelerated since 2013 to a new high n 2021, with continued ocean warming and ocean acidification.

The report combines input from multiple United Nations agencies, national meteorological and hydrological services and scientific experts. It highlights impacts on food security and population displacement, harming crucial ecosystems and undermining progress towards the Sustainable Development Goals.

“The provisional WMO State of the Global Climate 2021 report draws from the latest scientific evidence to show how our planet is changing before our eyes. From the ocean depths to mountain tops, from melting glaciers to relentless extreme weather events, ecosystems and communities around the globe are being devastated. COP26 must be a turning point for people and planet,” said United Nations Secretary-General António Guterres.

“Scientists are clear on the facts.  Now leaders need to be just as clear in their actions. The door is open; the solutions are there. COP26 must be a turning point. We must act now – with ambition and solidarity – to safeguard our future and save humanity,” said Mr Guterres in a video statement.

The provisional State of the Climate 2021 report is released at the start of the UN Climate Change negotiations, COP26, in Glasgow. It provides a snapshot of climate indicators such as greenhouse gas concentrations, temperatures, extreme weather, sea level, ocean warming and ocean acidification, glacier retreat and ice melt, as well as socio-economic impacts.

It is one of the flagship scientific reports which will inform negotiations and which will be showcased at the Science pavilion hosted by WMO, the Intergovernmental Panel on Climate Change and the UK Met Office. During COP26, WMO will launch the Water and Climate Coalition to coordinate water and climate action, and the Systematic Observations Financing Facility to improve weather and climate observations and forecasts which are vital to climate change adaptation.

Key messages

Ocean

Around 90% of the accumulated heat in the Earth system is stored in the ocean, which is measured through Ocean Heat Content.

The upper 2000m depth of the ocean continued to warm in 2019 reaching a new record high. A preliminary analysis based on seven global data sets suggests that 2020 exceeded that record. All data sets agree that ocean warming rates show a particularly strong increase in the past two decades and it is expected that the ocean will continue to warm in the future.

Much of the ocean experienced at least one ‘strong’ Marine Heatwave at some point in 2021 – with the exception of the eastern equatorial Pacific Ocean (due to La Niña) and much of the Southern Ocean. The Laptev and Beaufort Sea in the Arctic experienced “severe” and “extreme” marine heatwaves from January to April 2021.

The ocean absorbs around 23% of the annual emissions of anthropogenic CO2 to the atmosphere and so is becoming more acidic. Open ocean surface pH has declined globally over the last 40 years and is now the lowest it has been for at least 26,000 years. Current rates of pH change are unprecedented since at least that time. As the pH of the ocean decreases, its capacity to absorb CO2 from the atmosphere also declines.

1960-2020 ensemble mean time series
1960-2020 ensemble mean time series and ensemble standard deviation of global ocean heat content anomalies relative to the 2005-2017 climatology. Von Schuckmann et al., 2020.

World Meteorological Organization (WMO), 31 October 2021. Full article.


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