By Chris Lang
In September 2007, a paper by a group of Brazilian researchers was published in Geophysical Research Letters. The title was “Regional climate change over eastern Amazonia caused by pasture and soybean cropland expansion”.
The opening line of the paper explains that,
Field observations and numerical studies revealed that large scale deforestation in Amazonia could alter the regional climate significantly, projecting a warmer and somewhat drier post-deforestation climate.
The researchers looked at a business-as-usual scenario of deforestation that involved the clearing of the rainforest to make way for cattle ranching and soy plantations. They found that air temperatures in eastern Amazonia would increase, and rainfall would decrease.
In 2007, when the paper was written, about 15% of the Brazilian Amazon had been deforested, largely due to cattle ranching and agriculture. The expansion of soy plantations played “a major role in the last few years” the researchers write.
The authors predict that if current deforestation trends continued, about 40% of Amazon forests would be destroyed by 2050. Large areas of the Amazon have soils, climate and topography that are suitable for industrial agriculture.
The authors write that,
The Amazon has entered a new era as the growing profitability of cattle ranching and soy production increases deforestation rates and drives the expansion of the highway network into the region’s core.
They conclude with a dire warning:
The reduction in precipitation can create favorable conditions to potentially alter the structure of the forests, and lead to a process of savannization . . . .
One of the papers they cite to back up this statement was written in 1991. That paper, titled “Amazonian Deforestation and Regional Climate Change” points out that deforestation could lead to a longer dry season in the southern Amazon, “which could have serious implications for the reestablishment of the tropical forests following massive deforestation since rainforests only occur where the dry season is very short or nonexistent”.
Amazon tipping point
In February 2018, Thomas Lovejoy and Carlos Nobre published an editorial in the journal Science Advances. Nobre is one of the authors of the 2007 paper – and the 1991 paper. Nobre is a Member of the Brazilian Academy of Sciences and Senior Fellow of World Resources Insitute Brazil. Lovejoy is University Professor in the Department of Environment Science and Policy at George Mason University. He’s worked in Brazil’s Amazon since 1965.
In their editorial, Lovejoy and Nobre note that the Amazon generates about half of its own rainfall. Moisture is recycled five to six times as the air moves over the Amazon basin from the Atlantic towards the Andes in the west.
Lovejoy and Nobre ask the tipping point question: “[H]ow much deforestation would be required to cause the cycle to degrade to the point of being unable to support rain forest ecosystems”?
The 2007 paper that Nobre co-authored showed that “at about 40% deforestation, central, southern and eastern Amazonia would experience diminished rainfall and a lengthier dry season, predicting a shift to savanna vegetation to the east”.
In 2018, Lovejoy and Nobre write that,
We believe that the negative synergies between deforestation, climate change, and widespread use of fire indicate a tipping point for the Amazon system to flip to non-forest ecosystems in eastern, southern and central Amazonia at 20-25% deforestation.
They note that the serious droughts in 2005, 2010, and 2015-2016 “could well represent the first flickers of this ecological tipping point”. Severe floods in 2009, 2012 (and 2014 in southwest Amazonia) “suggest that the whole system is osciallating”.
The dry season in the southern and eastern Amazon has been increasing for the past two decades.
Lovejoy and Nobre argue that the deforested area should be kept to less than 20%, because “there is no point discovering the precise tipping point by tipping it”.
The tipping point is here
In December 2019, Lovejoy and Nobre wrote another editorial in Science Advances.
“Although 2019 was not the worst year for fire or deforestation in the Amazon, it was the year when the extent of fires and deforestation in the region garnered full global attention,” they write.
When rain falls on the Amazon rainforest, at least 75% of the moisture returns to the atmosphere. When the forest is destroyed, more than 50% of the rainwater runs off and is not available to recycle.
“Current deforestation is subtantial and frightening,” Lovejoy and Nobre write. “17% across the entire Amazon basin and approaching 20% in the Brazilian Amazon.”
Dry seasons are hotter and longer. Wet climate tree species are dying in greater number. Dry climate species are showing resilience.
The editorial is not written in a dry academic style: “The precious Amazon is teetering on the edge of functional destruction and, with it, so are we.”
The authors conclude that “The tipping point is here, it is now.”
False solutions
In their 2019 editorial, Lovejoy and Nobre call for a “new vision of the Amazon” that would exclude “illogical and short-sighted economies such as the unreliable mono-cutures of cattle, soybeans, and sugarcane”.
So far so good. But Lovejoy and Nobre also argue that a major reforestation project is “the only sensible way forward” especially in the southern and eastern Amazon. They don’t mention the problem, raised in the paper Nobre co-authored in 1991, of re-establishing rainforest in a climate with a longer dry season.
They say nothing about what species of trees would make sense – and which would be problematic. They do not discuss, for example, the problems created by eucalyptus monocultures in Brazil, particularly for communities living near them.
The authors make no mention of land rights, indigenous peoples’ rights, or climate justice.
Lovejoy and Nobre also suggest that reforestation would “qualify Brazilian states for support under the new California Tropical Forest Standard, which allows states not only to get financial support from carbon-capped California companies but could also bring positive attention to the country and draw support and assistance from the rest of the world”.
Unfortunately, Lovejoy and Nobre make no mention of the fact that carbon trading schemes, such as California’s, do not actually reduce greenhouse gas emissions. The climate crisis means that forest fires are more likely and occur more frequently. And generating carbon offsets from reforestation in Brazil would guarantee continued emissions from burning fossil fuels in California. The result? More global heating. More forest fires.
Lovejoy and Nobre also propose that,
A modern vision of the Amazon must include truly innovative elements to create profitable bioeconomies through, for example, sensible use of intact forests, the harnessing of power from its massive flowing rivers, or the sustainable harvesting of biological and biomimetic assets within Amazonian biodiversity.
It isn’t at all clear what “sensible use of intact forests” might entail. The history of logging in the Amazon, whether under the guise of “sustainable forest management” or not has been disastrous for the forests, for the climate, and for the indigenous peoples who live there.
Lovejoy and Nobre do not discuss the enormous environmental and social impacts of hydropower dams in the Amazon basin. Brazil is currently carrying out a dam-building boom. In a 2017 article for Yale Environment 360, Philip Fearnside, an ecologist at the National Institute for Research in Amazonia (INPA) in Brazil, describes the impacts as follows:
Brazil is in the midst of a dam-building spree in the Amazon basin that is changing the face of the world’s largest tropical forest region. The boom is driven by the country’s agricultural and heavy industrial interests, is being carried out with little regard to the impacts on indigenous people and the environment, is proceeding with little effort to capitalize on the nation’s vast renewable energy potential, and is often fueled by corruption.
And Lovejoy and Nobre make no mention of the dangers of biopiracy – the stealing of indigenous knowledge for the profit of multinational pharma corporations.
Lovejoy and Nobre are obviously correct to raise the alarm about deforestation in the Amazon. And they are no doubt correct that we are rushing headlong towards a tipping point where the Amazon rainforest ecosystem will flip, resulting in vast losses of biodiversity and carbon.
But the “solutions” they are proposing will only end up exacerbating the problem.
Dear Chris
Your op-ed is welcome, since it raises important points about the future of the Amazon.
First, the question of the tipping point. This is a case where the results of a climate model are used to support claims that are not supported by the current data. These climate models use, as their initial conditions, a representation of the deforestation that does not match the actual pattern. The models extract a huge continuous area at the centre of the forest and considers the outcomes. This spatial pattern is artificial. The actual geographical distribution of the deforestation is not as continuous as the models represent. It is rather a mix of dense forests (especially in protected areas), disturbed and degraded forest (mostly in Mato Grosso) and deforested area. Even a casual inspection using Google Maps shows that the initial condition of the climate model used by Nobre and co-authors does not match the reality in the ground.
While cannot affirm that a “tipping point” does not exist, the current scientific evidence (based on the existing models) is not sufficient to affirm (as Nobre and Lovejoy do) that we are heading towards an irreversible situation. To do that, one would need more sophisticated climate models, which could represent mesoscale processes of cloud formation over small areas (relative to the current resolution of the models). The problem is that developing such models takes time, and scientists are anxious with society’s inability to act.
The discussion of a “tipping point” in the Amazon is an exemplary case study of the balance between the desired rigour of Science versus the need to alert society of the imminent climate and environmental catastrophe. When distinguished scientists alert society about an “irreversible tipping point”, based on models that are not fully appropriate, are they doing us a service? Is this a defensible position?
In the case of the Amazon, I believe there are enough sound scientific evidences to defend the forest without recourse to the question of a “tipping point”. Let’s look at the data. In the period 2005-2015, when Amazon deforestation fell by almost 80% from the 2004 level, agricultural production in Brazil skyrocketed. In the same period, total agricultural production in Brazil doubled for R$ 12 billion to R$ 25 billion. Unlike the uncertain evidence for the “tipping point”, the case for reducing deforestation and improving production and economic gains is crystal-clear. Brazil does not need to deforest the Amazon for its agribusiness to thrive.
The second point concerns the issue of forest restoration. Here, I believe you may have misunderstood the position of Nobre and Lovejoy. It is conceivable they are defending the Forest Code, which mandates forest restoration in all farms that cut more than 20% of their land. In fact, such forest restoration is a key part of the Brazilian commitments to the Paris agreement. One also considers that Nobre and Lovejoy would favour, as most scientists in Brazil do, the use of passive restoration, which would, slowly but surely, lead to a long-term recovery of both biomass and biodiversity.
As for the trading schemes, you are completely correct to point out that there is no benefit to the world from carbon trading schemes that involve forests. Indeed, the official position of the Brazilian government has always been that protecting the Amazon should not be associated to any tradable carbon credits. This position is unlikely to change. Given that the opportunity costs associated with forest protection are limited (as the economic data shows), there is no justification for Brazil to sell forest carbon credits in the market. This would be bad for Brazil and worse for the planet.
Thanks for your work on the REDD debate, a key issue for the future of the planet,
Best regards
Gilberto
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Prof Dr Gilberto Camara is currently Secretariat Director of GEO – Group on Earth Observations and was General Director of INPE (Brazil’s National Institute for Space Research) from 2006 to 2012.