The Amazon rainforest, often called the lungs of our planet, is buckling under the pressure of rampant deforestation and climate change. Now, another threat is emerging, and scientists worry it could push this essential ecosystem over the edge. It’s looking increasingly likely that this El Niño, which arrived in June, will become the strongest on record. The latest forecasts show sea surface temperatures in the equatorial Pacific Ocean peaking around 7.2 degrees Fahrenheit (4 degrees Celsius) in December, obliterating the previous record and supercharging global temperatures. El Niño alters weather patterns around the world, and in the Amazon, it typically worsens drought and wildfires. The stronger the El Niño, the more likely it is that these expected outcomes will occur. In a Nature news feature, several researchers express concern that this event could push the rainforest past its “tipping point,” a critical threshold at which runaway drought, wildfire, and tree death cause the ecosystem to collapse and transition to a degraded savanna. This would be devastating not only for regional communities, biodiversity, and weather patterns, but also for the global climate, as the Amazon stores an amount of carbon equivalent to 15 to 20 years of global CO2 emissions.