GENEVA, May 18, 2022 (BSS/AFP) - Four key climate change indicators all set

new record highs in 2021, the United Nations said Wednesday, warning that the
global energy system was driving humanity towards catastrophe.

Greenhouse gas concentrations, sea level rise, ocean heat and ocean
acidification all set new records last year, the UN's World Meteorological
Organization (WMO) said in its "State of the Global Climate in 2021" report.

The annual overview is "a dismal litany of humanity's failure to tackle
climate disruption", UN chief Antonio Guterres said.

"The global energy system is broken and bringing us ever closer to climate
catastrophe.

"We must end fossil fuel pollution and accelerate the renewable energy
transition before we incinerate our only home."

The WMO said human activity was causing planetary-scale changes on land, in
the ocean and in the atmosphere, with harmful and long-lasting ramifications
for ecosystems.

- Record heat -

The report confirmed that the past seven years were the top seven hottest
years on record.

Back-to-back La Nina events at the start and end of 2021 had a cooling effect
on global temperatures last year.

Even so, it was still one of the warmest years ever recorded, with the
average global temperature in 2021 about 1.11 degrees Celsius above the pre-
industrial level.

The 2015 Paris Agreement on climate change saw countries agree to cap global
warming at "well below" 2C above average levels measured between 1850 and
1900 -- and 1.5C if possible.

"Our climate is changing before our eyes," said WMO chief Petteri Taalas.

"The heat trapped by human-induced greenhouse gases will warm the planet for
many generations to come. Sea level rise, ocean heat and acidification will
continue for hundreds of years unless means to remove carbon from the
atmosphere are invented."

- 'Consistent picture of warming world' -

Four key indicators of climate change "build a consistent picture of a
warming world that touches all parts of the Earth system", the report said.

Greenhouse gas concentrations reached a new global high in 2020, when the
concentration of carbon dioxide (CO2) reached 413.2 parts per million (ppm)
globally, or 149 percent of the pre-industrial level.

Data indicate that they continued to increase in 2021 and early 2022, with
monthly average CO2 at Mona Loa in Hawaii reaching 416.45 ppm in April 2020,
419.05 ppm in April 2021, and 420.23 ppm in April 2022, the report said.

Global mean sea level reached a new record high in 2021, rising an average of
4.5 millimetres per year throughout 2013 to 2021, the report said.

GMSL rose by 2.1 mm per year between 1993 and 2002, with the increase between
the two time periods "mostly due to the accelerated loss of ice mass from the
ice sheets", it said.

- Signs in the seas -

Ocean heat hit a record high last year, exceeding the 2020 value, the report
said.

And it is expected that the upper 2,000 metres of the ocean will continue to
warm in the future -- "a change which is irreversible on centennial to
millennial timescales", said the WMO, adding that the warmth was penetrating
to ever deeper levels.

The ocean absorbs around 23 percent of the annual emissions of human-caused
CO2 into the atmosphere. While this slows the rise of atmospheric CO2
concentrations, CO2 reacts with seawater and leads to ocean acidification.

The UN's Intergovernmental Panel on Climate Change concluded with "very high
confidence" that open ocean surface acidity is at the highest "for at least
26,000 years".

Meanwhile the report said the Antarctic ozone hole reached an "unusually deep
and large" maximum area of 24.8 million square kilometres in 2021, driven by
a strong and stable polar vortex.

Guterres proposed five actions to jump-start the transition to renewable
energy "before it's too late".

Among them, he suggested ending fossil fuel subsidies, tripling investments
in renewable energy and making renewable energy technologies, such as battery
storage, freely-available global public goods.

"If we act together, the renewable energy transformation can be the peace
project of the 21st century," Guterres said.