Rising global temperatures are on the verge of causing catastrophic harm to human health, according to a recent report.

The Global Tipping Points report, authored by a team of 160 scientists in about two dozen countries, concludes that global warming is on track to exceed 1.5 degrees Celsius, bringing the world closer to irreversible tipping points of melting ice shelfs, Amazon rainforest deforestation and bleached coral reefs. Unless there is an immediate intervention, the effects will lead to life-threatening floods, extreme heat and food insecurity, the scientists predict.

"This grim situation must be a wake-up call that unless we act decisively now, we will also lose the Amazon rainforest, the ice sheets and vital ocean currents," study co-author Mike Barrett, PhD, a chief scientific advisor at World Wildlife Fund-UK, said in a news release. “In that scenario, we would be looking at a truly catastrophic outcome for all humanity.”

Human-caused climate change has made record-breaking extreme heat, flooding and other disasters the norm for billions of people worldwide. But reaching multiple tipping points means deadly consequences for human health will become relentless, the report said.

“Each of those has its own really significant risks for humans that include worsening of extreme heat, worsening of really severe wildfires where wildfire smoke, with all its impacts on cardiovascular and respiratory health, can affect millions of people,” Linda Rudolph, MD, MPH, a senior policy advisor on climate and health at the Public Health Institute, told The Nation’s Health. “Unknown changes in rainfall and temperature in large parts of the populated world, risks in crop loss and significant changes in temperature really increase pressures on migration.”

Among the threats to human health that will grow is extreme flooding. People swept up in floods are at risk of drowning or serious injury, drinking water sources can become contaminated and damage to homes, roads and other infrastructure can wreak havoc on human health for years.

“Roads get closed,” Catharina Giudice, MD, an emergency physician who just completed the Tri-Institute Climate and Human Health Physician Fellowship, told The Nation’s Health. “People lose electricity. Hospitals may be surrounded by floodwaters and people can’t access the hospital. Ambulances can’t access people…There’s usually an increase in overall mortality that lingers on way, way beyond the acute event because people can’t access the regular care. They can’t access their medications. And it takes a long time for that infrastructure to be rebuilt.”

Countries must ramp up efforts to remove carbon from the atmosphere and drastically reduce emissions such as methane to cut greenhouse gas emissions in half by 2030 and reach net zero by 2050, the report said. That means more policies that phase out fossil fuel dependence and promote “positive tipping points” through continued adoption of wind energy, solar energy, and electric vehicles. Climate litigation has also played a role in enforcing existing climate policies and reducing harmful emissions. As of June, over 3,000 climate-related cases were filed worldwide, according to a review from Columbia Law School’s Sabin Center for Climate Change Law. 

Giudice said the world should not lose hope in mitigating the threats to human life. Effective policy and changes by industry, nations and populations can still make a difference. 

“Our ability to mitigate will determine how much we have to adapt to,” Giudice said. “So if we have great policies and efforts that transition us to green energy, then our adaptation efforts are not going to be as expensive and as difficult as if we had only focused on adaptation.”   

The report was issued in advance of the 2025 U.N. Climate Change Conference, which is being held through Nov. 21 in Brazil. The meeting, known as COP30, is focusing on moving from promises to action in tackling climate change. Delegates from more than 190 countries — who do not include U.S. officials — are pushing for stronger commitments to reduce emissions, particularly in high-polluting sectors such as energy and industry, while also addressing ways to help vulnerable communities adapt to rising seas and extreme weather. While progress has been made, delegates have clashed on issues such as fossil fuel emission cuts and financing.

“We are all aware of the headwinds,” Simon Stiel, U.N. climate change executive secretary said at the start of the meeting's second week. “But I also sense a deep awareness of what's at stake, and the need to show climate cooperation standing firm in a fractured world."

An attendee holds up a sign during the United Nation's Climate Change Conference in November in Belém, Brazil. Photo courtesy UN Climate Change via Flickr Creative Commons.