Human-induced warming increased over the last decade at a rate “unprecedented in the instrumental record”
By AFP
June 18, 2025
Dire future climate impacts worse than what the world has already experienced are already baked in over the next decade or two. - Copyright AFP Brendan SMIALOWSKI
Marlowe HOOD
From carbon pollution to sea-level rise to global heating, the pace and level of key climate change indicators are all in uncharted territory, more than 60 top scientists warned Thursday.
Greenhouse gas emissions from burning fossil fuels and deforestation hit a new high in 2024 and averaged, over the last decade, a record 53.6 billion tonnes per year — that is 100,000 tonnes per minute — of CO2 or its equivalent in other gases, they reported in a peer-reviewed update.
Earth’s surface temperature last year breached 1.5 degrees Celsius for the first time, and the additional CO2 humanity can emit with a two-thirds chance of staying under that threshold long-term — our 1.5C “carbon budget” — will be exhausted in a couple of years, they calculated.
Investment in clean energy outpaced investment in oil, gas and coal last year two-to-one, but fossil fuels account for more than 80 percent of global energy consumption, and growth in renewables still lags behind new demand.
Included in the 2015 Paris climate treaty as an aspirational goal, the 1.5C limit has since been validated by science as necessary for avoiding a catastrophically climate-addled world.
The hard cap on warming to which nearly 200 nations agreed was “well below” two degrees, commonly interpreted to mean 1.7C to 1.8C.
“We are already in crunch time for these higher levels of warming,” co-author Joeri Rogelj, a professor of climate science and policy at Imperial College London, told journalists in a briefing.
“The next three or four decades is pretty much the timeline over which we expect a peak in warming to happen.”
– ‘The wrong direction’ –
No less alarming than record heat and carbon emissions is the gathering pace at which these and other climate indicators are shifting, according to the study, published in Earth System Science Data.
Human-induced warming increased over the last decade at a rate “unprecedented in the instrumental record”, and well above the 2010-2019 average registered in the UN’s most recent Intergovernmental Panel on Climate Change (IPCC) report, in 2021.
The new findings — led by the same scientists using essentially the same methods — are intended as an authoritative albeit unofficial update of the benchmark IPCC reports underpinning global climate diplomacy.
They should be taken as a reality check by policymakers, the authors suggested.
“I tend to be an optimistic person,” said lead author Piers Forster, head of the University of Leed’s Priestley Centre for Climate Futures.
“But if you look at this year’s update, things are all moving in the wrong direction.”
The rate at which sea levels have shot up in recent years is also alarming, the scientists said.
After creeping up, on average, well under two millimetres per year from 1901 to 2018, global oceans have risen 4.3 mm annually since 2019.
– What happens next? –
An increase in the ocean watermark of 23 centimetres — the width of a letter-sized sheet of paper — over the last 125 years has been enough to imperil many small island states and hugely amplify the destructive power of storm surges worldwide.
An additional 20 centimetres of sea level rise by 2050 would cause one trillion dollars in flood damage annually in the world’s 136 largest coastal cities, earlier research has shown.
Another indicator underlying all the changes in the climate system is Earth’s so-called energy imbalance, the difference between the amount of solar energy entering the atmosphere and the smaller amount leaving it.
So far, 91 percent of human-caused warming has been absorbed by oceans, sparing life on land.
But the planet’s energy imbalance has nearly doubled in the last 20 years, and scientists do not know how long oceans will continue to massively soak up this excess heat.
Dire future climate impacts worse than what the world has already experienced are already baked in over the next decade or two.
But beyond that, the future is in our hands, the scientists made clear.
“We will rapidly reach a level of global warming of 1.5C, but what happens next depends on the choices which will be made,” said co-author and former IPCC co-chair Valerie Masson-Delmotte.
The Paris Agreement’s 1.5C target allows for the possibility of ratcheting down global temperatures below that threshold before century’s end.
Ahead of a critical year-end climate summit in Brazil, international cooperation has been weakened by the US withdrawal from the Paris Agreement.
President Donald Trump’s dismantling of domestic climate policies means the United States is likely to fall short on its emissions reduction targets, and could sap the resolve of other countries to deepen their own pledges, experts say.
Climate change could cut crop yields up to a quarter
By AFP
June 18, 2025
Farmers in many regions are already experiencing longer dry spells, unseasonable heatwaves and erratic weather due to climate change - Copyright AFP/File STR
Marlowe HOOD
Climate change is on track to reduce by 11 percent in 2100 the yields that today provide two-thirds of humanity’s calories from crops, even taking into account adaptation to a warming world, scientists said Wednesday.
As soon as 2050, this “moderate” scenario in which greenhouse gas emissions peak around 2040 and slowly taper off — a trajectory aligned with current trends — would see global losses of nearly eight percent.
And if carbon pollution worsens, the loss of calories across the same six staples — corn, wheat, rice, soybeans, sorghum and cassava — rises to nearly a quarter by century’s end, the researchers reported in Nature.
More generally, every additional degree Celsius of warming reduces the world’s ability to produce food from these crops by 120 calories per person per day, or nearly five percent of current daily consumption, they calculated.
“If the climate warms by three degrees, that’s basically like everyone on the planet giving up breakfast,” said co-author Solomon Hsiang, a professor at the Stanford Doerr School of Sustainability in California.
The steepest losses will occur at the extremes of the agricultural economy: in modern, Big Ag breadbaskets that currently enjoy some of the world’s best growing conditions, and in subsistence farming communities that typically rely of small cassava harvests.
North America would be hit hardest, losing a fifth of yields by 2100 in the moderate carbon pollution scenario, and two-fifths if emissions from burning fossil fuels continue apace.
Working with more than a dozen scientists, Hsiang and co-leader Andrew Hultgren, an assistant professor at the University of Urbana-Champaign, sifted through data from more than 12,000 regions in 55 countries.
– Erratic weather –
Previous calculations of how a warming world will impact crop yields generally failed to consider the ways in which farmers would adapt, such as switching crop varieties, shifting planting and harvesting dates, and altering fertiliser use.
The scientists estimated such adjustments would offset about a third of climate related losses over the next 75 years in the scenario of rising emissions, but that residual impacts would still be devastating.
“Any level of warming, even when accounting for adaptation, results in global output losses for agriculture,” said Hultgren.
With the planet about 1.5C hotter than preindustrial levels in the late 1900s, farmers in many regions are already experiencing longer dry spells, unseasonable heatwaves and erratic weather that undermines yields.
The nutritional value of most crops also declines with hotter temperatures, earlier research has shown.
The study revealed sharp variations in the impact of global warming on different crops and regions.
In the “worst-case” scenario of rising carbon emissions, corn yields would plummet 40 percent by 2100 across the grain belt of the United States, eastern China, central Asia, and the Middle East.
For soybeans, yields in the US would decline by half, and increase by a fifth in Brazil.
Wheat losses would drop by a fifth in eastern and western Europe, and by 30 to 40 percent in other wheat-growing regions: China, Russia and North America.
Cassava would be hit hard everywhere it’s grown.
“Although cassava does not make up a large portion of global agricultural revenues, it is an important subsistence crop in low- and middle-income countries,” the researchers pointed out.
Among the six crops examined, rice is the only one that stands to benefit in a warmer climate, mainly due to warmer nights.
By AFP
June 18, 2025
Farmers in many regions are already experiencing longer dry spells, unseasonable heatwaves and erratic weather due to climate change - Copyright AFP/File STR
Marlowe HOOD
Climate change is on track to reduce by 11 percent in 2100 the yields that today provide two-thirds of humanity’s calories from crops, even taking into account adaptation to a warming world, scientists said Wednesday.
As soon as 2050, this “moderate” scenario in which greenhouse gas emissions peak around 2040 and slowly taper off — a trajectory aligned with current trends — would see global losses of nearly eight percent.
And if carbon pollution worsens, the loss of calories across the same six staples — corn, wheat, rice, soybeans, sorghum and cassava — rises to nearly a quarter by century’s end, the researchers reported in Nature.
More generally, every additional degree Celsius of warming reduces the world’s ability to produce food from these crops by 120 calories per person per day, or nearly five percent of current daily consumption, they calculated.
“If the climate warms by three degrees, that’s basically like everyone on the planet giving up breakfast,” said co-author Solomon Hsiang, a professor at the Stanford Doerr School of Sustainability in California.
The steepest losses will occur at the extremes of the agricultural economy: in modern, Big Ag breadbaskets that currently enjoy some of the world’s best growing conditions, and in subsistence farming communities that typically rely of small cassava harvests.
North America would be hit hardest, losing a fifth of yields by 2100 in the moderate carbon pollution scenario, and two-fifths if emissions from burning fossil fuels continue apace.
Working with more than a dozen scientists, Hsiang and co-leader Andrew Hultgren, an assistant professor at the University of Urbana-Champaign, sifted through data from more than 12,000 regions in 55 countries.
– Erratic weather –
Previous calculations of how a warming world will impact crop yields generally failed to consider the ways in which farmers would adapt, such as switching crop varieties, shifting planting and harvesting dates, and altering fertiliser use.
The scientists estimated such adjustments would offset about a third of climate related losses over the next 75 years in the scenario of rising emissions, but that residual impacts would still be devastating.
“Any level of warming, even when accounting for adaptation, results in global output losses for agriculture,” said Hultgren.
With the planet about 1.5C hotter than preindustrial levels in the late 1900s, farmers in many regions are already experiencing longer dry spells, unseasonable heatwaves and erratic weather that undermines yields.
The nutritional value of most crops also declines with hotter temperatures, earlier research has shown.
The study revealed sharp variations in the impact of global warming on different crops and regions.
In the “worst-case” scenario of rising carbon emissions, corn yields would plummet 40 percent by 2100 across the grain belt of the United States, eastern China, central Asia, and the Middle East.
For soybeans, yields in the US would decline by half, and increase by a fifth in Brazil.
Wheat losses would drop by a fifth in eastern and western Europe, and by 30 to 40 percent in other wheat-growing regions: China, Russia and North America.
Cassava would be hit hard everywhere it’s grown.
“Although cassava does not make up a large portion of global agricultural revenues, it is an important subsistence crop in low- and middle-income countries,” the researchers pointed out.
Among the six crops examined, rice is the only one that stands to benefit in a warmer climate, mainly due to warmer nights.
