{"id":37423,"date":"2023-02-20T14:48:32","date_gmt":"2023-02-20T17:48:32","guid":{"rendered":"https:\/\/www.raisg.org\/?p=37423"},"modified":"2023-02-23T14:51:30","modified_gmt":"2023-02-23T17:51:30","slug":"why-is-the-amazon-so-important-for-climate-change","status":"publish","type":"post","link":"https:\/\/www.raisg.org\/es\/radar\/why-is-the-amazon-so-important-for-climate-change\/","title":{"rendered":"Why Is the Amazon So Important for Climate Change?"},"content":{"rendered":"

SCIENTIFIC AMERICAN
\n20 de febrero, 2023
\nEmma Bryce<\/a><\/p>\n

 <\/p>\n

Here\u2019s why the Amazon rain forest is key to protecting Earth from the detrimental effects of climate change<\/p>\n

Viewed from high above, the Amazon in South America is a lush emerald quilt, home to millions of animals and the planet\u2019s largest river by volume. It is also key to protecting our planet from the detrimental effects of\u00a0climate change<\/a>.<\/p>\n

But why? And what could happen to the global climate if we lost it?<\/p>\n

The Amazon\u2019s sheer size\u2014it covers nearly\u00a0seven million square kilometers<\/a>, or about the area of Australia\u2014makes it shine on the climate stage. With so many trees covering such an enormous swath of land, everything the forest \u201cdoes\u201d is big and impactful. Some of its actions are downright unique: The Amazon makes its own weather, generating some of its rainfall and keeping itself cool, while also stabilizing regional temperatures. Add that to the gobs of\u00a0greenhouse gas<\/a>\u00a0that its biomass stores and you\u2019ve got a natural climate protector. Yet\u00a0we are steadily dismantling this valuable landscape<\/a>, aggravating climate change in several ways scientists are just beginning to understand.<\/p>\n

Giant Carbon Sponge<\/strong><\/p>\n

All Earth\u2019s forests impact the atmosphere.\u00a0Trees draw down carbon dioxide<\/a>\u00a0from the atmosphere through photosynthesis, locking away that greenhouse gas in leaves, trunks, roots and nearby soil. The Amazon\u2019s sheer volume of trees makes it one of the world\u2019s largest carbon sinks. \u201cThe Amazon today, even with all the deforestation, stores more than 150 billion [metric] tons of carbon,\u201d says Carlos Nobre, an Earth systems scientist at the University of S\u00e3o Paulo in Brazil\u00a0and a longtime researcher of the climate and ecological effects of Amazon deforestation. Roughly half the Amazon\u2019s carbon store is in the soil. The other half is in its trees, which contain\u00a0about 20 percent<\/a>\u00a0of all the carbon captured by vegetation across the planet.<\/p>\n

But when humans cut down those trees, that biomass\u00a0releases its stored carbon<\/a>\u00a0back into the atmosphere as CO2<\/sub>, where it has a warming effect. Like other greenhouse gases, carbon dioxide molecules prevent heat on Earth from escaping back into space. The agriculture and mining industries are steadily cutting down the Amazon\u2019s dense network of\u00a016,000 tree species<\/a>. Altogether, deforestation has stripped\u00a017 percent\u00a0<\/a>of the rain forest\u2019s tree cover since 1970.<\/p>\n

Deforesting industries often clear an area by setting fires, which rapidly release stored carbon into the atmosphere. Trees left unburned but cut decompose, also releasing their carbon. The fires help to explain why parts of the Amazon forest now\u00a0emit more CO2<\/sub>\u00a0than they absorb<\/a>. Fires also send up plumes of soot that screen sunlight and add to warming.<\/p>\n

Making It Rain<\/strong><\/p>\n

The warming atmosphere feeds back into the forest. As the globe heats up, the frequency and severity of\u00a0weather phenomena associated with drought<\/a>\u00a0are increasing over South America, says Nobre, who is also co-chair of the Science Panel for the Amazon, which supports research and initiatives to save the rain forest. The effects are creating longer regional dry periods and less rainfall, driving tree\u00a0die-offs<\/a>. Dryness and declining forest cover also\u00a0increase the risk<\/a>\u00a0of natural fires.<\/p>\n

Tree loss brings other consequences, Nobre says. During the dry season, more intense sunshine causes vast amounts of water\u2014stored in trees and soils from wet periods\u2014to transpire<\/a>. That water vapor \u201creaches the lower atmosphere and becomes clouds and rain again,\u201d Nobre explains. \u201cOne molecule of water vapor that enters the Amazon recycles between five to eight times,\u201d he adds, illustrating the importance of this hydrological engine in recharging regional rainfall. Ample rains also have a cooling effect,\u00a0just as sweating can cool a person<\/a>\u00a0off after a workout.<\/p>\n

If tree cover declines, so will the water store, and with it, more of the forest. Past\u00a0research\u00a0<\/a>led by Nobre showed that a cycle of warming, drying and forest shrinkage could push the Amazon to a minimum\u00a0threshold of tree cover<\/a>, below which the forest would irreversibly degrade into a simpler grassland habitat.<\/p>\n

What if the Forest Vanishes?<\/strong><\/p>\n

Estimates vary on the exact\u00a0threshold at which the Amazon would disappear. Nobre and others suggest it could be a loss of just\u00a020 to 25 percent<\/a>\u00a0of the Amazon\u2019s predeforestation tree cover (bearing in mind the forest has already lost 17 percent). There are also variable figures on how swiftly the forest could degrade once it passes the threshold. But already, parts of the southern Amazon are transitioning into what Nobre describes as \u201copen canopy degraded ecosystems.\u201d This is a landscape with sparse tree cover, containing \u201ctremendously reduced biodiversity,\u201d that stores a fraction of the carbon of an intact rain forest, Nobre says.<\/p>\n

If the forest fades away, and its trees release their massive carbon store, what does that mean for global climate?<\/p>\n

The Amazon\u2019s estimated 150-billion-ton-plus carbon bank is the equivalent of more than 10 years\u2019 worth of global fossil fuel emissions, Nobre says. If the entire Amazon degraded into an open, savannalike landscape, local rainfall would decline by up to 30 percent, with consequences felt as far as Colombia and Argentina, where rainfall cycles are partially fed by moisture from the Amazon, Nobre explains. Without the forest\u2019s surface-cooling effect<\/a>, regional temperatures would rise\u00a0by several degrees<\/a>.<\/p>\n

The forest loss would resonate across the globe. \u201cIf you put [carbon dioxide] into the atmosphere, it quickly diffuses all over the world,\u201d says Elena Shevliakova, a physical scientist at Geophysical Fluid Dynamics Laboratory, part of the U.S. National Oceanic and Atmospheric Administration, who has modeled the climate effects of Amazon loss. Releasing, say, 120 billion metric tons of CO2<\/sub>\u00a0(a more conservative estimate of Amazon carbon stores) by removing forest would warm the planet by an estimated 0.25 degree\u00a0Celsius, she explains.<\/p>\n

Even if the world reduced human-caused emissions enough to get on track to fulfill the\u00a0Paris climate agreement<\/a>, keeping global warming below a 1.5-degree-C increase from preindustrial levels, the sudden loss of the Amazon and its stored carbon would put that target out of reach. Global emissions reductions are\u00a0not currently on target<\/a>, which should raise the concern about the impact of the Amazon\u2019s degradation, Shevliakova says.<\/p>\n

To protect this planetary gem, Nobre says the international community urgently needs to curb deforestation and greenhouse gas emissions, and, where possible,\u00a0reforest<\/a>\u00a0the degraded swathes. Saving the Amazon is also entwined with the rights of Indigenous peoples; a\u00a0growing body<\/a>\u00a0of research<\/a>\u00a0suggests that lands stewarded by Indigenous peoples are deforested less.<\/p>\n

Even if the emerald biome seems like a distant world, everyone on Earth is connected to its fate, Shevliakova says. \u201cLosing the Amazon is going to affect everybody,\u201d she adds.<\/p>\n

Tomado de: https:\/\/www.scientificamerican.com\/article\/why-is-the-amazon-so-important-for-climate-change1\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Viewed from high above, the Amazon in South America is a lush emerald quilt, home to millions of animals and the planet\u2019s largest river by volume. It is also key to protecting our planet from the detrimental effects of climate change.<\/p>\n

But why? And what could happen to the global climate if we lost it?<\/p>\n

The Amazon\u2019s sheer size\u2014it covers nearly seven million square kilometers, or about the area of Australia\u2014makes it shine on the climate stage. With so many trees covering such an enormous swath of land, everything the forest \u201cdoes\u201d is big and impactful. Some of its actions are downright unique: The Amazon makes its own weather, generating some of its rainfall and keeping itself cool, while also stabilizing regional temperatures. Add that to the gobs of greenhouse gas that its biomass stores and you\u2019ve got a natural climate protector. Yet we are steadily dismantling this valuable landscape, aggravating climate change in several ways scientists are just beginning to understand.<\/p>\n","protected":false},"author":327,"featured_media":37424,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-37423","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-radar","category-2","description-off"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/posts\/37423","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/users\/327"}],"replies":[{"embeddable":true,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/comments?post=37423"}],"version-history":[{"count":1,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/posts\/37423\/revisions"}],"predecessor-version":[{"id":37427,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/posts\/37423\/revisions\/37427"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/media\/37424"}],"wp:attachment":[{"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/media?parent=37423"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/categories?post=37423"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.raisg.org\/es\/wp-json\/wp\/v2\/tags?post=37423"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}