Expected CO2 levels in 2024 threaten 1.5C warming limit: Met Office Jan 22, 2024

Climate-emissions-warming

By Kelly MACNAMARA

Paris, Jan 19, 2024 (AFP) - Increased carbon dioxide in the atmosphere this

year will exceed key trajectories for limiting warming to 1.5C, Britain's Met

Office predicted Friday, with researchers reaffirming that that only "drastic"

emissions cuts can keep the target in sight.

Rising emissions from fossil fuels and deforestation are set to be

compounded in 2024 by the cyclical El Nino weather phenomenon, which reduces

the ability of tropical forests to absorb carbon.

The Met forecast this will drive a "relatively large" rise in annual

average CO2 concentrations measured this year at the Mauna Loa Observatory in

Hawaii - around 2.84 parts per million (ppm) higher than in 2023.

Researchers said that will likely take the world outside the main pathways

set out by the UN's Intergovernmental Panel on Climate Change (IPCC) to limit

warming to 1.5 degrees Celsius above pre-industrial levels - the more

the ambitious goal of the 2015 Paris Agreement.

"It's looking vanishingly unlikely that we'll limit warming to 1.5,"

Richard Betts, the Met Office author of the CO2 forecast, told AFP.

"Technically speaking, we could still do it if emissions were to be reduced

drastically starting immediately, but the scenarios that the IPCC uses show

the buildup of CO2 in the atmosphere slowing already to meet that

target."

Scientists warn that the world is edging closer to experiencing individual

years of warming of 1.5C or more, although that would not by itself amount to

a breach of the Paris target, which is measured over an average of roughly two

decades.

The IPCC has already suggested that if emissions continue as they are, the

world would breach 1.5C in the early 2030s.

"We're not seeing any signs of avoiding that in terms of the buildup of CO2

in the atmosphere," Betts said.

- Warming effect -

The UN's World Meteorological Organization last week confirmed that 2023 was the

the warmest year on record "by a huge margin", putting the annual average global

temperature at 1.45C above pre-industrial levels (1850-1900).

This year could be even hotter because of the naturally-occurring El Nino

climate pattern, which emerged mid-2023, usually increases global temperatures

for one year after.

El Nino also brings hotter and drier conditions across tropical forests and

peatlands that reduce their ability to absorb carbon from the atmosphere.

Normally around half of humanity's emissions are taken back out of the

atmosphere by ecosystems and absorption in the ocean.

"That free service is weakened when an El Nino is happening, so that

means more of our emissions are staying in the atmosphere this year," Betts

said.

There was particular concern over regions of the Amazon, which have already

seen severe drought, heat, and fires, he added.

UN experts have calculated that emissions need to be slashed nearly in half

this decade to keep the 1.5C limit in play.

But carbon pollution has continued to increase.

Mauna Loa, which has been monitoring atmospheric CO2 levels since 1958, has

traced a trend line that may fluctuate but has generally continued to climb.

To predict CO2 concentrations this year at Mauna Loa, considered

representative of global averages, the Met Office uses emissions data combined

with observations and forecasts of ocean surface temperatures in the

equatorial east Pacific - an indicator for El Nino.

Betts said that even without the El Nino effect, the estimated buildup of

CO2 in the atmosphere would be at the "very, very upper limit of consistency"

with the IPCC 1.5C scenarios.

He stressed that while these are not the only ways to keep the 1.5C limit

in reach, all possible paths would involve "urgent emissions cuts".

   By Kelly MACNAMARA

klm/tw

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