Climate change: However, plant cover increases

30/04/2015

Paradoxically, despite the brutal deforestation of the rainforest, the Earth's vegetation cover has increased in size.

The great initiatives of reforestation in China, the extension of bushes and the new situation in the former Soviet Union have caused this phenomenon of global increase of the vegetal layer in the soils.

Generally, the environmental impact of China or Russia is very badly talked about, as well as the phenomenon of thermal oscillation known as El Niño (ENSO), which causes periods of alternate droughts with intense rains in many parts of the planet. However, a study shows that these three actors, despite the deforestation of tropical forests, are making the planet green again.

The vegetable layer on the floors is the basis of life. On it are born, grow, rest and develop the ecosystems on which humans depend. Plant cover is also the first line of defense against climate change. Forests, pastures and cultivated fields remove a quarter of the CO from the atmosphere₂ anthropogenic, mostly produced by fossil fuels, which is heating the planet. Therefore, every hectare deforested in the Amazon rainforest, in Africa or in Indonesia, becomes a global drama.

However, in a study published in Nature Climate Change with data from several satellites over a period of 20 years, scientists have proven that large areas of Russia, China, northern Australia, southern Africa and even eastern Brazil They are recovering green. This despite the deforestation of tropical forests, since it is being compensated with reforestation in other parts of the planet in the last decade.

«Despite continued deforestation in South America and Southeast Asia, we have found that the decline in these regions has been offset by the recovery of non-tropical forests and new growth in the arid savannas and bushlands of Australia. , Africa and South America»says the scientist at the Center for Climate Change Research at the University of New South Wales, Australia, and the study's lead author, Yi Liu.

Among other elements that have raised the indexes of increase of the vegetable layer is the abandonment of collectivized farms after the fall of the Soviet Union, which has increased the vegetation cover in Russia.

Within the gains of forest mass and, therefore, withdrawal of CO₂ of the atmosphere, those obtained in Russia and China stand out. Satellite measurements show that in both countries vegetation cover has increased in recent decades, although for very different reasons. «In Russia, forests have naturally occupied abandoned farmland after the fall of communism. Meanwhile, in China, massive tree reforestation projects have contributed a significant amount to global biomass"Liu maintains, adding that"between both actors, compensate more than half of the carbon loss due to tropical deforestation«.

Specifically, the loss of rainforests has led to a reduction in its capacity to retain carbon stolen from the atmosphere of about 210.000 tons of CO₂ (Tm / CO₂) between 2003 and 2012. For its part, the new plant cover in Russia and China captures 100.000 and 70.000 Tm / CO every year₂ respectively. If we take into account that the contribution of tropical forests to the total is 44%, for an 17% of temperate and boreal forests, China and Russia deserve applause.

To this we add the progress of the areas of bushes, areas of shrubs and cultivated fields. There are several factors that are raising the protagonism of these actors such as: changes in land use, better agricultural techniques, fire reduction.

In this reality there are key elements, since there is evidence that one reason is the increase in the efficiency in the use of water due to the increase in CO₂ in the atmosphere.

It may seem a paradox, but the CO₂ It is bad for the climate but not for the plants, as the director of the Global Carbon Project says, the Catalan Josep Canadell.

As in a greenhouse, with a higher concentration of carbon dioxide, the stomata of the plant (pores in the leaves that allow it to breathe) do not have to open as much to take the same amount of CO₂, losing with this less water they can use to grow more.

The other factor has to do with the El Niño thermal oscillation and its reverse, La Niña. This phenomenon, which begins in the Pacific Ocean, affects rain patterns, alternating very dry periods with months of torrential rains in areas where savannas or scrub dominate.

«Climate change is bringing more variability to the climate and, therefore, to the cycles of boom and collapse. We have studied these cycles and vegetation grows more when there is more rain than is lost when there is less, so we believe that the end result is that the systems can capture more carbon«explains the executive director of the Global Carbon Project.

However, this increase in the greenness of the planet is not enough. As Canadell recalls: «we know that about 50% of emissions from human activities remain in the atmosphere even after the other half is removed by terrestrial vegetation and oceans. The only way to stabilize the climate system is to reduce fossil fuel emissions to zero«.

Source: Blueberrieschile.cl