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Brazil votes on 4 October with Amazon clearing at half its 2022 rate
Amazon clearing has halved since Lula restored the environmental agencies in 2023. The Brazilian researchers who watch the forest expect a win for Flavio Bolsonaro to push the rate back up toward its 2021 peak.
The Scientist · Science desk
What happened
- Brazilians elect a president on 4 October, with Jair Bolsonaro under house arrest and ineligible and his son Flavio, a 45-year-old senator, on the ballot against President Lula.
- Annual Amazon deforestation rose from 7536 square kilometres in 2018 to 11,594 in 2022, with 2021 the highest year in 15, across Jair Bolsonaro's presidency from 2019 to 2023.
- Lula returned in 2023 and restored the environmental agencies' powers, and clearing fell to 5731 square kilometres in the year from August 2024 to July 2025.
- Flavio Bolsonaro's campaign promises zero illegal deforestation by 2029, and in a recent television interview he declined to say climate change exists, speaking of extreme climate events and cyclical periods.
- His campaign did not respond to questions about its environmental policy, and the environment has had little attention in a race dominated by a corruption scandal involving him.
Compiled by The ScientistSomething wrong?How this is made
Why it matters
- decision Modellers holding a Brazil line have to decide whether 5731 square kilometres a year is a trend or a policy-dependent level, and a high-clearing case built on 2022 is set below the 2021 peak it is meant to represent.
- constraint The monitoring record counts area cleared, so it constrains what can be said about emissions without a separate carbon density assumption per hectare.
- exposure Protection written into statute can be withdrawn by a legislature, while rebuilding agency capacity took Lula most of a term. APIB says Indigenous lands would be opened to critical-mineral extraction.
- contradiction The same 2029 target can be met two ways: clearing stops, or clearing is legalised. Which one is meant changes whether the pledge is a constraint on the forest frontier at all.
The rise under Jair Bolsonaro came to 4058 square kilometres of extra clearing a year by 2022, 54 per cent above the 2018 level [1]. The fall since has been larger: about 51 per cent below 2022, and about a quarter below the 2018 figure that preceded his term [2][3]. One caveat on putting those percentages side by side. The 5731 figure is given for a specific window, August 2024 to July 2025, while the 2018 and 2022 figures are given as annual totals [7][5][6].
This is one country and two administrations, in sequence. There is no second Brazil kept under the old rules, so commodity prices and weather are not held constant. The sequence does offer a named intervention with the right timing: Lula restored the power of the environmental agencies after returning to office in 2023, and the clearing figure came down by half [7].
For anyone carrying a Brazil line in a forest-carbon model, the quantity on offer is area. New Scientist describes the 4.2 million square kilometres of Brazilian Amazon as holding "huge stocks of carbon" [8], and turning cleared area into emissions takes a carbon density per hectare, which is a separate parameter. The peak year is dated to 2021 and called a 15-year high, without a value [4]. Since the 2022 total was 11,594 square kilometres in the same series, the 2021 peak sits above that [5], so a high-clearing case anchored on 2022 understates the worst year of the last Bolsonaro government. At the current rate, clearing runs at about 0.14 per cent of the standing forest each year [4].
The campaign pledge is zero illegal deforestation by 2029 [11]. Philip Fearnside, an ecologist at Brazil's National Institute for Amazonian Research, said: "There are two ways to achieve that. One is to actually stop deforestation. The other, more likely way, is to just legalise the deforestation that's going on." [10] Illegality is a statutory category. As a senator, Flavio Bolsonaro proposed legislation criticised as a threat to Brazil's native vegetation, and he has said he would appoint five new supreme court judges [26][17].
Claudio Angelo, international policy coordinator at Brazil's Climate Observatory, said: "This is a do-or-die moment for the Amazon, really." [9] He also said a Bolsonaro government could move faster than the first one did, drawing on the political know-how it acquired: "Wildcat mining would explode, deforestation would go up and everything we already had during the first Bolsonaro administration would come back even stronger." [18]
Izabella Teixeira, Brazil's environment minister from 2010 to 2016, said of the candidate: "But we do know he is a climate change denialist and believes environmental protections are irrelevant." [13] A spokesperson for Lula's campaign told New Scientist that a second term would be about "implementing and gaining scale", with a focus on tougher enforcement, adaptation and Brazil's 2035 climate targets [15].
What to watch
- The next August-to-July clearing figure, covering 2025 to 2026, will show whether the 5731 level holds independently of who wins.
- Whether the Flavio Bolsonaro campaign publishes an environmental platform.
- Whether native-vegetation legislation and supreme court appointments move early in any new term. Either one could redefine what counts as illegal clearing.