Myths, truths about Amazon fires

As fires have blazed across the Amazon in recent weeks, they’ve captivated the world. Politicians, celebrities and citizens — from French President Emmanuel Macron to Portuguese soccer star Cristiano Ronaldo — have expressed concern about the damage being done in the region.

But something else has also been spreading: misconceptions.

Myths have been propagating about the Amazon rainforest that will not help — and could exacerbate — the problem that these fires have caused. One fact remains quite clear: The fires in the Amazon constitute an emergency situation that could grow much worse in the coming weeks.

And the attention focused on the Amazon now is an opportunity to set in motion a long-term Brazilian strategy to keep the Amazon healthy.

So, what’s true and what’s false? It’s time to set the record straight.

1: The Amazon forest is the ‘lungs’ of the Earth since it provides 20% of the world oxygen supply

False. There is a very large stock of oxygen in the atmosphere and the net contribution of the Amazon to this stock is quite small. The Amazon forest produces an enormous amount of oxygen each year through photosynthesis, but it also consumes an enormous amount each year through respiration — yes, trees breathe. The net flux of oxygen to the atmosphere varies from year to year, but on average is close to zero.

2: The Amazon forest is on fire

This is true — with a caveat. We do not know how much virgin Amazon forest — the parts that have never been logged or burned — is on fire right now. Virgin forests in the Amazon are very resistant to fire in normal years but lose that resistance when severe droughts occur. The Amazon is not currently experiencing a severe drought, although we are only halfway through the dry season.

Fires in virgin Amazon forests are, in general, very low to the ground — you can step over them — because of the deep shade and high humidity of the forest interior that keep the leaves and twigs damp. As a result, they are usually not detected by satellites. When you see photos of Amazon forests with fire up in the tree crowns, they are most likely forests that have been logged for timber or that were damaged in previous years by a fire.

We do know there is a large area of dead forest that is burning this year. These are patches of forest that were cut down with chainsaws, allowed to dry, and are now being set on fire to make way for cattle pasture of crops. These fires are big, release huge amounts of smoke, and are very hard to control.

3: The Amazon is approaching a ‘tipping point’ beyond which it will be very difficult to save

This is true. We are seeing the early signs of a vicious, downward spiral of drought, fire and tree death that is, in my opinion, the biggest threat to the Amazon in a warming world.

Much of the rainfall in the Amazon is created by the forest itself — through the vapor produced by the forest when water evaporates from tree leaves high off the ground. When forest is cut down, less water vapor goes into the air and droughts become more likely. As deforestation and climate change cause more severe droughts, fires in virgin forests will become more frequent and extensive.

These seemingly innocuous fires kill many of the forest’s giant trees, and when those trees crash to the ground, the forest becomes even more vulnerable to further burning, especially when highly flammable grasses and shrubs invade the damaged areas.

4. The number of fires in the Amazon this year is unprecedented

False. The number is high but it is not unprecedented. So far, it’s been the biggest fire year since 2010.

Based on statistics from the Global Fire Emissions Database, the number of fires in Brazilian Amazon states through August this year is 25% higher than the average number of fires in the same period from 2010-2018. The number of fires each year is correlated with the area of deforestation and the severity of the drought during the dry season.

5. Amazon deforestation is skyrocketing

Deforestation is climbing, but is still below its historical average. From 1996 through 2005, deforestation in the Amazon averaged roughly 20,000 square kilometers per year. It declined 77% to 4,600 square kilometers in 2012 through an expansion of the forest area under protection, a crackdown on illegal clearing, and restrictions on farm credit and has been rising slowly since then.

Preliminary estimates of Amazon deforestation in 2019 indicate that deforestation is increasing, headed toward the highest annual rate in a decade, totaling 5,884 square kilometers from January through August.

6. The Amazon forest is doomed

This is false in the near term. The Amazon can be saved if Brazil and other Amazon nations improve their programs for fighting forest fires and re-establish forest cover that has been destroyed. Allowing the forests to grow back naturally and actively restoring forest on degraded land can reverse many of the negative impacts from deforestation.

The good news is that the most damaging fires — those that burn virgin forests — are also the easiest to put out. The key is to spot these fires early and respond rapidly with teams of local farmers and farm hands who have been trained in fire fighting techniques.

We have the tools to save the Amazon. We just have to use them.

The long-term prospects for the Amazon are more uncertain. If droughts become more severe and more frequent through climate change and deforestation, it may become very difficult or impossible to prevent a large-scale shift of the Amazon forest to fire-prone scrub vegetation.