Detailed NASA analysis finds Earth and Amazon in deep climate trouble

In view of the current nonstop rise in greenhouse gas emissions responsible for intensifying climate change, NASA researchers this year posed two key questions: When will the planet’s temperature likely reach an annual average of 2° Celsius (3.6° Fahrenheit) above preindustrial levels? And what will the global climate look like in great detail all over the world at that temperature?

Disturbingly, their findings indicate that a 2°C increase could be reached between 2041 and 2044 (under higher and lower emission scenarios, respectively) in comparison with the preindustrial period (1850-1900). The planet is currently at 1.15°C (2.07°F) above 19^th century levels, with most of this warming occurring since 1975.

A rise above 2°C could put Earth on track for catastrophic climate change impacts, according to the 2023 report by the U.N. Intergovernmental Panel on Climate Change.

A fine-scaled portrait of Earth 2040

To investigate the potential multiple effects of a 2°C planet, scientists at the NASA Earth eXchange analyzed the projections of 35 of the world’s leading climate models with a very high resolution that gives results for areas of just 25 square kilometers (9.6 square miles). Many climate models currently use a far coarser resolution of 200 km2 (77 mi2). NEX fine-scaling allowed for estimated climate impact projections on both a local and regional scale, and even on a daily basis.

“If merged into a monthly average, a few days projected to be dangerously hot and humid could get lost in the numbers, concealing the risk for human lives,” explained study lead author Taejin Park, a researcher at NASA’s Ames Research Center. “Finer-scale information can help identify variations in projected climate change that may be overlooked, so leading to significant impacts on planning and decision-making.”

Six climate variables — air temperature, precipitation, relative humidity, short- and long wave solar radiation and wind speed — were analyzed for the 2040s, compared with a baseline period (1950–1979) and combined to assess the risks of two key climate indicators: heat stress (the joined effects of temperature and humidity on the human body, which can lead to permanent disability or death) and fire weather (the probability of conditions favorable to an increase in fires, a serious climate change threat).

Overall, the study found that most regions of the world will experience higher heat stress, with countries closer to the equator living a greater number of days considered extreme. “This does not necessarily mean that high and mid-latitude regions are not vulnerable to heat stress,” Park told Mongabay. “Because of their varying sensitivity and adaptive capability to heat, even lower levels of heat stress could result in significant impacts in such countries. This applies to other climate impact indicators [too], such as fires and floods.”

One worrying projected climate impact could particularly affect high- and mid-latitude countries in the northern hemisphere, the study found, “where most wind farms are currently operational or under construction.” Loss of wind intensity there in the future could compromise this renewable energy source.

“We have already witnessed the consequences of record-high global temperatures this summer. Heat waves, wildfires and floods occurred globally, albeit with varying timing and event types,” said the NASA scientist. “However, the projected changes in climate and their impacts will unfold gradually, day by day, month by month and year by year, rather than as a sudden change. So, every 10th or 100th degree increase matters to us and our Earth.”

The NASA study also shined a spotlight on the Amazon, which projections say could experience, not only higher temperatures, but also less rain, more severe drought, more winds and a greater risk of fire incidents. The Amazon could be the area on the planet with the greatest reduction in relative humidity, especially in the so-called Arc of Deforestation — a crescent-shaped zone of extensive human-caused rainforest loss stretching from Brazil’s Atlantic coast to its western border with Bolivia.

As a result, that region “could experience one of the most significant climate changes on Earth,” added Park. Those extremes could even trigger the overshoot of a tipping point, with the Amazon Rainforest transitioning rapidly to degraded savanna — adding massive amounts of stored carbon to the atmosphere, drastically worsening climate change.

Parts of Amazon have already seen 3°C of warming

It is already known that the extreme effects projected by the NASA study are starting to unfold in the Brazilian Amazon. But what wasn’t known until this year is that certain areas, such as the northwestern portion of the biome (in Amazonas and Roraima states) and in the interior of Pará state, as well as other parts of Brazil, such as the semiarid region of Bahia state, in the northeast, and Mato Grosso do Sul state in the savanna biome, have already seen extreme temperature increases of more than 3°C (5.4° F) just since the 1960s.

That discovery was made via a recent analysis by INPE, Brazil’s space agency, to support Brazil’s National Plan for Adaptation to Climate Change, a review conducted by the nation’s Ministry of the Environment.

“The northernmost regions of Brazil reveal the signal of climate change more intensely. Periods of great drought in humid environments contribute to the increase in temperatures, such as in the northwest of the Amazon, which has a low deforestation rate,” Lincoln Alves, INPE’s analysis coordinator, told Mongabay.

Global climate change alone, he said, does not explain the extreme warming seen in the Amazon. “Factors such as deforestation, degradation and urbanization amplify rising temperatures on a local scale. Regional warming, in turn, potentially increases the effects of climate change,” he said. “The fact that maximum temperatures have exceeded the [safe] limits established by the IPCC (Intergovernmental Panel on Climate Change] is very serious due to impacts on water resources, human health and agriculture, among others.”

According to Alves, it’s not possible to quantify Amazon regional temperatures between 1880 and 1960, since most measurements in Brazil didn’t begin until the 1960s. However, climatologist Carlos Nobre, co-president of the Science Panel for the Amazon and associate researcher at the University of São Paulo Institute of Advanced Studies, estimates that there was no significant temperature increase in the rainforest between 1880 and 1960, as extreme droughts only began after 1970, when deforestation intensified.

“All Brazilian biomes are much hotter,” said Nobre. “When vegetation cover is removed to plant soybeans, the soil loses water and, as a result, the temperature rises and the environment becomes drier, where it was previously very humid, as in the case of the Amazon. And the drier the vegetation, the more flammable it becomes, especially in the tropics.” More drought means more fires, which means less forest, which enhances drought in a vicious cycle.

In 1990-91, Nobre and fellow researchers published the first scientific articles warning of the Amazon climate tipping point, in which the rainforest biome could become a biome with a savanna climate. More than 30 years later, the rainforest has had an estimated 18% of its area deforested and 17% degraded.

“Due to the arc of deforestation — an area [stretching more than] 2,000 km [1,242 mi] from the Atlantic to the Bolivian Amazon — the dry season in the south of the Amazon lasts 4-5 months now, whereas it used to last in the late 1970s 3-4 months, at most. And it’s 20-30% hotter. Global warming induces longer droughts, and regions like the northwestern Amazon also become affected,” Nobre told Mongabay.

“If [the planet’s] temperature reaches 1.5°C [above preindustrial levels], plus degradation, fires and deforestation, the south, center and east of the Amazon will pass the tipping point,” he emphasized. “The region will have even more intense droughts and we will lose between 50% and 70% of the forest, releasing 250 billion tons of CO2 into the atmosphere. The maximum we can emit [planetwide] for the temperature to stay at 1.5°C is 400 billion tons of CO2. This includes everything, the burning of fossil fuels, agribusiness, etc. The Amazon alone represents [nearly] three-quarters of this limit.”

Park further observes that there has been concern about the concept of a [sudden] tipping point. “It could create the false impression that the Amazon is safe below a certain threshold of deforestation and doomed above it, similar to the concept of a 2ºC or 1.5ºC [global] warming limit. [But] The projected climate changes and their impacts will manifest gradually, unfolding over days, months, and years, as opposed to occurring suddenly.”

Loss of biodiversity and ecosystem services

According to Eric Bastos Gorgens, a professor of forestry engineering at the Federal University of Jequitinhonha and Mucuri Valleys, forests need to be understood as communities that find balance and stability in tremendous biodiversity — a state in which species can coexist and evolve. But extreme climate change disrupts that stability: “Species that are less tolerant of drought, lightning storms, intense winds and higher temperatures will have their populations reduced, posing serious risks to diversity,” he said.

“In general, trees have defense systems for extreme situations. These protection mechanisms, however, have a cost, and when the frequency of those events increases, the cost is too high and the trees end up dying. In a climate change scenario, we can expect an increase in the area of physiognomies [types of vegetation] more adapted to conditions with limited resources, such as [that found today in] the Cerrado [savanna] biome,” Gorgens told Mongabay.

The increase in maximum temperature could also reshape ecological and biological cycles, including for tree species, said Vitor Gomes, an environmental scientist at the Federal University of Pará. “Climate change has [already] been causing significant impacts on the diversity and composition of edible flora species of the Brazilian Amazon. Along with deforestation, it has affected ecosystem services, such as climate regulation and utility species,” meaning those with a use for people as medicine, food or other purposes.

Gomes and scientists from the Naturalis Biodiversity Center and Oxford University, among other institutions, just completed two studies to be published in 2024. They found that the loss of ecosystem services related to tree species in the Pan-Amazon reflected, up to 2018, a loss of $1.5 trillion per year.

“This shows that even a variation of around 1°C in the global average temperature [which we’ve already seen] has major impacts on natural ecosystems, in particular tropical forests,” Gomes said.

Drying Amazon arteries

In addition to intensifying climate effects, the Amazon is currently under the influence of a strengthening El Niño, a natural cycle occurring every few years that warms the equatorial waters of the central and eastern Pacific Ocean and the North Tropical Atlantic. The heating up of both oceans inhibits the formation of rains in north and northeast Brazil, while also making the Amazon more susceptible to fire.

Since September, a severe drought has caused Amazon watercourse levels in the western portion of the biome to fall far more than in previous dry seasons. In October, some streams reached or approached their lowest watermarks in 120 years. Among these are navigable waterways, such as the Amazon River, Rio Negro and the Tapajós, Solimões and Madeira rivers, though the last two have recently begun recovering volume.

As the drought worsened, fish died by the thousands. In Lake Tefé and Lake Coari along the Middle Solimões River in Amazonas state, 228 pink dolphins (Inia geoffrensis) and tucuxis (Sotalia fluviatilis) have been found dead since September. Researchers are investigating, but believe the mammals in Lake Tefé may have suffered heat stress: As water volume fell there, the lake overheated to 39°C (102°F). In Lake Coari, water temperature didn’t rise as much, topping out at 34°C (93°F). But a higher concentration of Euglena sanguinea algae was detected there, potentially toxic to fish, though there are no studies finding it harmful to mammals.

In addition to fish being a vital source of protein for Indigenous and traditional peoples, the Amazon’s many rivers are vital for transporting people and supplies. With the drying up of the Solimões River, the inhabitants of the Porto Praia de Baixo and Boará/Boarazinho Indigenous lands, in the Tefé region, were left isolated and without fish.

In Boará/Boarazinho, the stream turned into a trickle of muddy liquid. Without access to clean water since August, the residents of Nova Esperança do Arauir village were forced to drink from the fetid stream. Outbreaks of diarrhea, vomiting and stomach pain became common. The extreme drought in Amazonas caused its state government to declare an emergency in all of its 62 municipalities.

Dário Kopenawa Yanomami, vice president of the Hutukara Yanomami Association, gave his perspective on what is happening to the Amazon and the planet. “The Earth is our mother and has been suffering for a long time. Like a human being who feels pain, she feels when invaders, agribusiness, mining and oil companies cut down thousands of trees and dig deep into the ground, into the sea. She is asking for help and giving warnings so that non-Indigenous people stop tearing the skin off the Earth.”

Despite all the warnings from scientists and Indigenous peoples about the embattled state of our planet, the world’s big fossil fuel companies, supported by compliant national governments, plan to expand their production, according to a recent U.N. report. Among those countries is the United Arab Emirates, which just hosted COP28 in Dubai — talks that the petrostate planned to use to make new oil deals. With Azerbaijan, another petrostate, poised to host next year’s COP29, many analysts are pessimistic about the possibility for significant climate action.

Banner image: Since September, a record drought that is likely to continue into 2024, has besieged the Amazon. At least 228 freshwater dolphins have died in lakes connected to rivers, possibly killed by excess heat. This photo was taken Oct. 2, 2023. Image courtesy of Miguel Monteiro/Instituto Mamirauá.

Citations:

Park, T., Hashimoto, H., Wang, W., Thrasher, B., Michaelis, A. R., Lee, T., et al. (2023). What does global land climate look like at 2°C warming? Earth’s Future, 11, e2022EF003330. doi: https://doi.org/10.1029/2022EF003330

SEI, Climate Analytics, E3G, IISD, and UNEP. (2023). The Production Gap: Phasing down or phasing up? Top fossil fuel producers plan even more extraction despite climate promises. Stockholm Environment Institute, Climate Analytics, E3G, International Institute for Sustainable Development and United Nations Environment Programme. doi: https://doi.org/10.51414/sei2023.050

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