Planetary scientists in a new report have concluded that we could soon cross a threshold in Earth’s temperatures leading to boiling hot temperatures and towering seas in the decades and centuries to come.
An international team of climate researchers, writing in the journal, Proceedings of the National Academy of Sciences, says the warming expected in the next few decades could turn some of the Earth's natural forces - that currently protect us - into our enemies.
Such processes include permafrost thaw; the loss of methane hydrates from the ocean floor; weaker land and ocean carbon sinks; the loss of Arctic summer sea ice and the reduction of Antarctic sea ice and polar ice sheets, said the report.
Even if countries succeed in meeting their CO2 targets, we could still lurch on to an "irreversible pathway". Global warming by just 1.5 degrees Celsius risks pushing the Earth into a lasting and dangerous "hothouse" researchers warned on Monday.
The Arctics will likely see its first ice-free summer before mid-century, and -- in a 2C world -- could be that way one-in-every-four years. Over the last four decades, minimum sea ice extent has dropped by about 40 percent.
"These tipping elements can potentially act like a row of dominoes. Once one is pushed over, it pushes Earth towards another," said Johan Rockstrom, co-author of the report and executive director of the Stockholm Resilience Centre.
"It may be very difficult or impossible to stop the whole row of dominoes from tumbling over. Places on Earth will become uninhabitable if 'Hothouse Earth' becomes the reality," he added.
If polar ice continues to melt, forests are slashed and greenhouse gases rise to new highs—as they currently do each year—the Earth will pass a tipping point.
Crossing that threshold "guarantees a climate 4-5 Celsius higher than pre-industrial times, and sea levels that are 10 to 60 meters (30-200 feet) higher than today," cautioned scientists in the Proceedings of the National Academy of Sciences.
And that "could be only decades ahead," they said. Scientists from the Stockholm Resilience Center, the University of Copenhagen, Australian National University and the Potsdam Institute for Climate Impact Research worked on the study.
A 2015 Paris climate agreement between countries aimed to keep global warming below 2 degrees Celcius, compared with pre-industrial levels. But according to the report, the risk of tipping cascades could be significant at a 2 degrees C temperature rise - and could increase sharply beyond that point.
How to slow global warming down?
People must immediately change their lifestyle to be better stewards of the Earth, the researchers said.
Fossil fuels must be replaced with low or zero emissions energy sources, and there should be more strategies for absorbing carbon emissions such as ending deforestation and planting trees to absorb carbon dioxide.
Soil management, better farming practices, land and coastal conservation and carbon capture technologies are also on the list of actions.