Tree loss brings more warming as world heats

(Climate News Network, 27 Aug 2019) Blazing forests cannot dampen climate change, tree loss will worsen it, and poorly nourished trees will make the next century more challenging.

As global temperatures soar, tree loss will mean the world’s forests may no longer be able to function fully as safe stores for atmospheric carbon dioxide.

Forests play a key role in the effort to contain climate change driven by human combustion of fossil fuels. But as the Arctic burns and fires race through the Amazon forest four new studies cast doubt on whether the planetary canopy can keep up.

The boreal forests of the north-west territories of Canada are home to vast tracts of spruce and other conifers: they cover soils so rich in carbon that a square metre could hold 75 kilograms of life’s most vital element.

But in 2014 wildfires made more probable by rising temperatures spread across more than 2.8 million hectares of Canada, turning at least 340,000 ha of the territories from a carbon sink into a source for more planet-heating greenhouse gas.

Limit to benefits

More carbon dioxide should fertilise more abundant growth in those forests not destroyed by fire and drought. But a new study from California and Spain warns that by 2100, the woodland world may reach breaking point. It isn’t clear that forests can go on benefiting from higher levels of carbon dioxide.

And new measurements from the Amazon, which in theory absorbs around a quarter of all human fossil fuel emissions each year, demonstrate why: the region’s soils are deficient in phosphorus. Without this vital element, the trees cannot take full advantage of the extra carbon fertilizer.

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Climate News Network, 27 Aug 2019: Tree loss brings more warming as world heats