WASHINGTON — Humans are transforming Earth’s natural landscapes so dramatically that as many as one million plant and animal species are now at risk of extinction, posing a dire threat to ecosystems that people all over the world depend on for their survival, a sweeping new United Nations assessment has concluded.

The 1,500-page report, compiled by hundreds of international experts and based on thousands of scientific studies, is the most exhaustive look yet at the decline in biodiversity across the globe and the dangers that creates for human civilization. A summary of its findings, which was approved by representatives from the United States and 131 other countries, was released Monday in Paris. The full report is set to be published this year.

Its conclusions are stark. In most major land habitats, from the savannas of Africa to the rain forests of South America, the average abundance of native plant and animal life has fallen by 20 percent or more, mainly over the past century. With the human population passing 7 billion, activities like farming, logging, poaching, fishing and mining are altering the natural world at a rate “unprecedented in human history.”

The Earth could be doomed to breach the symbolic 1.5C warming limit in as little as three years at current levels of carbon dioxide emissions.

That's the stark warning from more than 60 of the world's leading climate scientists in the most up-to-date assessment of the state of global warming.

Nearly 200 countries agreed to try to limit global temperature rises to 1.5C above levels of the late 1800s in a landmark agreement in 2015, with the aim of avoiding some of the worst impacts of climate change.

But countries have continued to burn record amounts of coal, oil and gas and chop down carbon-rich forests - leaving that international goal in peril.

Climate change has already worsened many weather extremes - such as the UK's 40C heat in July 2022 - and has rapidly raised global sea levels, threatening coastal communities.

"Things are all moving in the wrong direction," said lead author Prof Piers Forster, director of the Priestley Centre for Climate Futures at the University of Leeds.

"We're seeing some unprecedented changes and we're also seeing the heating of the Earth and sea-level rise accelerating as well."

These changes "have been predicted for some time and we can directly place them back to the very high level of emissions", he added.

The world’s ice sheets just got a dire prognosis, and coastlines are going to pay the price

Glaciers in Antarctica on February 7, 2022. A new study suggests even if the world meets its climate targets it may not be enough to save the planet's ice sheets. 

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The UN climate summit in the United Arab Emirates in 2023 ended with a call to "transition away from fossil fuels". It was applauded as a historic milestone in global climate action.

A recent, rapid heating of the world's oceans has alarmed scientists concerned that it will add to global warming.

This month, the global sea surface hit a new record high temperature. It has never warmed this much, this quickly.

Scientists don't fully understand why this has happened.

But they worry that, combined with other weather events, the world's temperature could reach a concerning new level by the end of next year.

Experts believe that a strong El Niño weather event - a weather system that heats the ocean - will also set in over the next months.