Trees Stalling Global Warming

Here’s a report about some positive change that’s happening. The process could be repeated in other regions, as a positive and inexpensive way to deter global warming, and its disastrous effects.  Comments afterwards.

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Very cool: trees stalling effects of

global heating in eastern US, study finds


Vast reforestation a major reason for ‘warming hole’ across

parts of US where temperatures have flatlined or cooled


Oliver Milman @olliemilman

The Guardian

17 Feb 2024


Trees provide innumerable benefits to the world, from food to shelter to oxygen, but researchers have now found their dramatic rebound in the eastern US has delivered a further, stunning feat – the curtailing of the soaring temperatures caused by the climate crisis.

While the US, like the rest of the world, has heated up since industrial times due to the burning of fossil fuels, scientists have long been puzzled by a so-called “warming hole” over parts of the US southeast where temperatures have flatlined, or even cooled, despite the unmistakable broader warming trend.

A major reason for this anomaly, the new study finds, is the vast reforestation of much of the eastern US following the initial loss of large numbers of trees in the wake of European settlement in America. Such large expanses have been reforested in the past century – with enough trees sprouting back to cover an area larger than England – that it has helped stall the effect of global heating. Mallory Barnes, an environmental scientist at Indiana University who led the research, said …


The reforestation has been remarkable

and we have shown this has translated

into the surrounding air temperature.

The ‘warming hole’ has been a real my-

stery and while this doesn’t explain all

of it, this research shows there is a really

important link to the trees coming back.”


There was a surge in deforestation from the start of the US’s early colonial history, as woodland was razed for agriculture and housing, but this began to reverse from around the 1920s as more people began to move into cities, leaving marginal land to become populated again with trees. The US government, meanwhile, embarked upon an aggressive tree-planting program, with these factors leading to about 15m hectares of reforested area in the past century in the eastern US.

The recovery of the US’s eastern forests has blunted global heating mainly through the trees’ transpiration, in which water is drawn up through the roots to the leaves and then released into the air as vapor, slightly cooling the surrounding area.

By poring over data from satellites and weather stations located across the eastern US from 1900 to 2000, Barnes and her colleagues found reforested areas have provided this cooling impact on a grand scale, with most of this effect occurring within 400 meters of the trees.

In all, the replenished forests today cool the eastern US by 1C to 2C (1.8F to 3.6F) each year. The cooling effect is strongest on the hottest days in summer, when trees lower temperatures by 2C to 5C (3.6F to 9F), the researchers found.

The researchers cautioned that bringing back trees hasn’t been the sole cause of the stalled warming, with factors such as airborne pollutants, which block incoming sunlight, and agricultural irrigation also potential causes. But Barnes said that the findings should further bolster efforts to provide thoughtful reforestation, particularly near urban communities that suffer particularly scorching temperatures due to a lack of shady trees. Barnes said …


“Trees have a really beneficial im-

pact upon surface temperatures

through transpiration, which is

similar to human sweating, and they

have really cooled things off a lot.


“Moving forward, we need to think

about tree planting not just as a way

to absorb carbon dioxide but also

the cooling effects in adapting for cli-

mate change, to help cities be resilient

against these very hot temperatures.”


Patrick Gonzalez, a University of California, Berkeley, climate change scientist and forest ecologist who wasn’t involved in the new study, said the work provides “strong support” to the theory of cooling trees. He said …


“Cutting carbon pollution from cars, power

plants and other human sources that burn

coal, oil and methane remains the essential

solution to halt climate change. Natural regen-

eration of trees and reforestation, where ecolo-

gically appropriate, can contribute substantially.”

Barnes, too, stressed that reforestation was no substitute for the need to drastically cut planet-heating emissions, which hit a new global high last year. She said …


“Nature-based climate solutions like tree

planting won’t get us out of this climate

change problem. If anyone thinks we can

just plant a few trees and be OK, they are

wrong – we need a massive reduction in

fossil fuel emissions to hit our targets.


“Reforestation is something that needs

to happen in addition to, not instead

of, cutting emissions.”


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Mass media gives priorities to alarm-raising news, following the “If it bleeds, it leads” guidelines for improving readership or viewership. When a positive outcome, such as this one, surfaces, it’s not likely to get widespread feature coverage. Yet, this reforesting outcome is positive, widespread, can become even more widespread, and is inexpensive to do.  Adding D’s comments …


“It is becoming obvious that trees are a piece of the solution to climate change. The article discusses the cooling impact of trees to a large area. Our recommendation it to plant trees near your home, so you will benefit from the cooling aspect of trees. You cannot control the whole world, but you can control the land that is yours. Trees provide shade from the heat.  And now we know they provide cooling to the land. Plant a tree – or ten – and enjoy the benefits.”


The only thought I’d add is that trees also filter toxins, absorb carbon dioxide, and add oxygen to the air, providing health benefits to nearby residents.

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