With the world currently on track for 2.7°C of average global warming by 2100, aggressive reductions in climate pollution are an imperative to avoid “catastrophic” harms to human health, says the latest in a series of reports from eminent medical journal The Lancet.

With the release of the report, an open letter signed by 46 million health professionals is urging COP President Sultan Al Jaber, who also serves as CEO of the Abu Dhabi National Oil Company, to “commit to an accelerated, just and equitable phaseout of fossil fuels and invest in a renewable energy transition.”

The findings of the 2023 Report of The Lancet Countdown on Health and Climate Change are grim. “Governments, the corporate sector, and banks continue to invest in oil and gas extraction and development even as the “challenges and costs of adaptation soar,” a level “negligence” that is generating “grave and mounting” threats to public health, the authors say in a release.

Any further delays on action to limit global temperature rise to 1.5°C pose a “catastrophic threat to the health and survival of billions of people all over the world and to successful adaptation efforts,” the authors add.

Already, “heat-related deaths in people aged over 65 increased by 85% in 2013-2022 compared to 1991-2000, substantially above the 38% increase expected had temperatures not changed,” based solely on changing demographics.

And higher temperatures mean more hunger. “More frequent heatwaves and droughts were responsible for 127 million more people experiencing moderate to severe food insecurity in 122 countries in 2021, than annually between 1981 and 2010,” says the report.

Higher heat can also make it too hot to work. Some 490 billion potential labour hours were lost globally to heat in 2022, “with income losses accounting for a much higher proportion of GDP in low- (6.1%) and middle-income countries (3.8%).”

Global heating also poses a devastating risk to healthcare systems.

Even at today’s average warming of 1.14°C), 27% of cities the Lancet authors surveyed reported health systems that are “being overwhelmed by the impacts of climate change.”

‘Much, Much Worse’ at 2°C

Permitting global temperatures to rise to 2°C by 2100 will be disastrous for human health, especially amongst the already vulnerable, The Lancet writes. Under such a scenario, “yearly heat-related deaths are projected to increase by 370% by mid-century, with heat exposure expected to increase the hours of potential labour lost globally by 50%.”

Meanwhile, “more frequent heatwaves could lead to around 525 million more people experiencing moderate to severe food insecurity by 2041-2060,” producing a higher global risk of malnutrition.

“In the face of such dire projections, adaptation alone cannot keep up with the impacts of climate change, and the costs are rapidly becoming unsurmountable,” said Prof. Stella Hartinger, director of the Lancet Countdown Regional Centre for Latin America.

“The root causes of climate change must be tackled through rapidly accelerating mitigation across all sectors to ensure the magnitude of health hazards do not breach the capacity of health systems to adapt,” she added. “Unless governments finally start to act on these warnings, things will get much, much worse,”

Governments Aren’t Getting the Memo

Yet government policies are still allowing climate pollution to rise, the authors say. The global energy system is the “biggest single contributor to global greenhouse gas emissions,” and that output grew 0.9% in 2020, to a record 36.8 billion tonnes. Such growth has been enabled by massive fossil fuel subsidies, provided at the direct expense of struggling health care systems.

“In 2020, 69 of 87 countries (responsible for 93% of all global carbon emissions) provided fossil fuel subsidies to the net value of $305 billion—exceeding 10% of national health spending in 26 of the countries, and 50% in 10 countries.”

The finance sector is also a huge contributor. “The 40 private banks that lend the most to fossil fuels collectively invested US$489 billion every year between 2017 and 2021 in the industry, and over half increased their lending since 2010-2016.”

All this support has allowed the world’s 20 largest fossils to increase production to levels that, should they continue unchecked, “would result in greenhouse gas emissions surpassing levels compatible with 1.5°C of warming by 173% in 2040.”

These recipients of state largesse “allocated just 4% of their capital investment to renewables in 2022,” The Lancet says, and may of the world’s biggest fossil companies have since cut back their energy transition investment.

‘Still Room for Hope’

But the authors stress that countries and communities can still take charge and begin driving down emissions.

“Empowering countries to transition from dirty fuels towards local, modern renewable sources of energy would not only bring immediate health benefits, but also reduce socio-economic and health inequities, by developing local skills, generating jobs, supporting local economies, and delivering energy to off-grid areas to electrify homes and health care facilities, particularly in areas where energy poverty still undermines people’s health and well-being,” said Prof. Ian Hamilton, Lancet Countdown Working Group Lead on Mitigation Actions and Health Co-Benefits.

A zero-carbon future will also bring a host of public health benefits around the world, with millions of deaths avoided every year thanks to cleaner air and better diets.

“There is still room for hope,” said Dr. Marina Romanello, executive director of the Lancet Countdown at University College London. “If climate negotiations [at COP 28] drive an equitable and rapid phaseout of fossils fuels, accelerate mitigation, and support adaptation efforts for health, the ambitions of the Paris agreement to limit global heating to 1.5 °C are still achievable, and a prosperous, healthy future lies within reach.”