IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, do you know what’s in your sunscreen, and that it moves from your skin into your blood? We’ll talk about that. But first, the Amazon rainforest is often called the planet’s lungs. In the process of growing and breathing, its trees suck up a quarter of the Earth’s carbon and produce a fifth of the world’s oxygen. 

So new data from the National Institute for Space Research in Brazil is of great concern. Researchers monitoring satellite images of Amazon tree cover found an alarming spike in the Amazon’s deforestation. In the first seven months of 2019, the rainforest lost 50% more trees than during the same time last year. 

That spike in tree loss coincides with Brazil’s new president, [INAUDIBLE] Jair Bolsonaro, taking office. And since January, he’s slashed environmental productions and has reportedly called the new deforestation data a lie. But climate scientists warn deforestation is pushing the Amazon rainforest to a tipping point that would disrupt both its ecosystem and the global climate. Dr. Carlos Nobre is a climate scientist at the University of Sao Paulo’s Institute of Advanced Studies. He joins us via Skype. Welcome to Science Friday. 

CARLOS NOBRE: Thank you very much. 

IRA FLATOW: So put this in perspective, would you? How alarming are these new numbers on deforestation? 

CARLOS NOBRE: The numbers are very worrying because Brazil, with most of the other Amazonian countries, for about 10 years, from 2004 to 2012, 2013, they were declining, over 70% deforestational rates. They were really moving towards almost a zero deforestation. And still, the production of agricultural products were increasing. So deforestation has nothing to do with agricultural production. So everybody was happy. 

But after 2014, deforestational rates started to climb back again. And this year, the last 12 months, have seen a spike, have seen a surge, a very troublesome serge. Very likely the last 12 months, we will see increase of 40% to 50% in deforestational rates in Brazil. Also, deforestational rates in Colombia are increasing. 

So this is a sign that we might be closer to the tipping point for the Amazon. If we deforest more than 25% of the forest in the Amazon basin, we might really ruin the Amazon forest with the move to a new system in which it becomes irreversible to maintain the forest, over 56% of the basin. 

IRA FLATOW: And now this spike in deforestation has happened under Brazil’s new president, Jair Bolsonaro. Does he understand this, that this is a danger? 

CARLOS NOBRE: I’m not sure the current president and his mostly– the ministers associated, particularly the Minister of Environment, have a full understanding of the risks that Brazil and the Amazon countries are under. Because you see the Amazon forest provides a lot of ecosystem service, for instance, recycling water vapor and increasing rainfall, keeping temperatures 2, 3 degrees cooler than without the forest. 

So these are all benefits, even for agricultural production south of the Amazon. And solely for the forest, it disappears. The life, the agricultural, the life of the people will be much worse without the forest. So I don’t think the president and his Minister of Agriculture understand the full consequences of continuing to deforest the Amazon. I think that their policies are aimed at the very short term gains in pushing the agricultural frontier, cattle, farms, and also soy plantations, into the Amazon. 

IRA FLATOW: So is it all about the money then? 

CARLOS NOBRE: It’s about short term gains. It’s about, really, seeing opportunities to increase production of those agricultural goods. But this is very short term because without the Amazon forest, even the productivity of cattle farms or crops will be diminished up to the point that you might not have suitable agricultural crop lands or grazing lands for cattle in the near future, and lasted 20, 30 years. 

IRA FLATOW: And what about the indigenous communities and their land in the Amazon? What are his policies on their rights? 

CARLOS NOBRE: Actually even when he was a House member for 28 years– the president was a House member– for a long time, he has defended the idea that the indigenous lands are too large in extent. They should not be demarcated anymore. And also now as the president, he’s tried to convert indigenous cultures into a different culture, into, let’s say, our culture– farmers, cattle ranchers. 

But that really goes very much against the cultural inheritance of these more than 300 different indigenous communities in the Brazilian Amazon. They want to keep their culture, which is a steady force culture, which is not only good for them, for their culture, but it’s also very important for the maintenance of climate stability for the planet. If the Amazon forest disappears, we will almost impossible to reach the targets of the Paris Agreement to keep the temperature of the planet less than 2 degrees warmer. 

IRA FLATOW: Well, is there going to be a tipping point in the rainforest where that happens? 

CARLOS NOBRE: A lot of scientific studies– and I’ve been involved in those studies for almost 30 years– they indicated that if we exceeded 20% to 25% of deforestation in the whole Amazon, or if we keep global warming unchecked and that the temperature in the Amazon region increased 4 degrees Celsius, we might really exceed and tip this balance and to transform 50%, 60%, up to 70% of the forest into a degraded savanna, with much less carbon, with much less biodiversity. 

So we are now currently at total deforestation is about 50%, 60% in the basin. And the Amazon is about 1.5 degrees warmer. So if we continue the deforestation rates as they are in the last few years, the tipping point will be exceeded, reached in something like 20 years. 

IRA FLATOW: And do you find anything, besides President Bolsonaro, in your way or in the way of making sure that doesn’t happen? 

CARLOS NOBRE: Well, we hope that he will listen to the voices of the people, of the Brazilian people, the Amazonian people. Because all polls conducted in the last 20 years, including polls conducted after he was elected, 90% of the Brazilians are against Amazon deforestation. So we hope democracy will have the last word. Every Brazilian, almost all Brazilians, nine out of 10, are against Amazon deforestation. So I hope eventually democracy will prevail, and he will listen to the voice of the people, including his electors, his voters, also against Amazon deforestation. 

IRA FLATOW: Well, let’s talk about it. If the rainforest does become a savanna, what does happen to the global climate? 

CARLOS NOBRE: Well, initially, there will be over the course of this transition, which might take between 30 and 50 years, a tremendous loss of carbon. The forest stores a lot of carbon underground, in the trunks, branches, et cetera. It’s a lot of carbon. It’s about 120 to 150 pounds of carbon per hectare. There are 10,000 square meters. 

A degraded savanna that might replace the forest is store something like 30 to 40. So we lose 70 to 80 tons of carbon per hectare that will end up in the atmosphere as carbon dioxide, again, complicating the global climate crisis. So if all this carbon ends up in the atmosphere, keeping, meeting the targets of the Paris Accord will become much, much less difficult, perhaps even impossible. So this is a very important fact. 

And also degraded savannas contain much less biodiversity. So we are talking about extinction of tens of thousands of species that exist only in the tropical forest. And the last but not less important, is the fact that perhaps one million people living in indigenous lands with their culture or their forest culture might be at the risk of losing the forest. 

IRA FLATOW: Are you hopeful about this? It seems very scary. 

CARLOS NOBRE: Well, I’m hopeful that first, of course, Brazil and all other Amazonian countries that are democracies, so people go out and vote. So I hope because this issue became so urgent, so critical with the increase in deforestational rates in the last few years, particularly in the last 12 months, that the voice of the people will be heard by all politicians, not only Brazil, but all Amazonian cultures, and that they will eventually start thinking harder and find ways of developing our countries without deforestation. 

IRA FLATOW: All right, we have to leave it there. And we hope we share your optimism. Dr. Carlos Nobre, climate scientist at the University of Sao Paulo’s Institute of Advanced Studies.

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