Paris (AFP) - As President Donald Trump prepares to announce whether he will pull America out of the 2015 Paris Agreement sanctioned by his predecessor and nearly 200 other world leaders, the stakes on climate change have never been higher.
Earth's average global temperature is scaling new heights, sea ice is retreating, extreme weather events have become more frequent and species are increasingly under threat, say scientists.
A summary of the evidence:
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1.1 degrees
In 2016, Earth's average surface temperature hit a record level for the third consecutive year since records began in 1880.
The global average temperature was about 1.1 degree Celsius (1.98 Fahrenheit) higher than the pre-industrial era. This is when mankind’s mass burning of coal, and later oil and gas, started hiking levels of heat-trapping carbon dioxide in the atmosphere.
The 21st century has already seen 16 of the 17 hottest years on record.
Some of the world's biggest cities may be as much as eight degrees Celsius (14.4 degrees Fahrenheit) hotter by 2100, said a recent study.
1.6 million square miles
Arctic summer sea ice shrank to 4.14 million square kilometres (1.6 million square miles) in 2016 — the second-lowest after 2012, when it reached 3.39 million km2.
The Arctic Ocean could be ice-free in summer as early as 2030. In parts of Arctic Russia, temperatures were 6 C to 7 C higher than the long-term average.
On the other extreme of the world, Antarctica, sea ice last year hit its lowest extent ever recorded by satellites.
High-altitude glaciers, meanwhile, declined in surface area in 2015 for the 36th year in a row.
On the other extreme of the world, Antarctica, sea ice last year hit its lowest extent ever recorded by satellites.
High-altitude glaciers, meanwhile, declined in surface area in 2015 for the 36th year in a row.
400 parts per million
The atmospheric concentrations of the three most potent greenhouse gases — carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) — all hit new highs in 2016.
For the first time on record, in 2015, the amount of CO2 in the atmosphere averaged 400 parts per million (ppm).
Most climate scientists agree that greenhouse gas concentrations in the atmosphere must be capped at 450 ppm of CO2 equivalent (CO2e) for a fighting chance to limit average global warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels.
This is the cap enshrined in the Paris Agreement.
Fossil fuel-generated greenhouse gas emissions are thought to have remained stable in 2016 for the third consecutive year, even as the global economy grew. But to stay on target for 2 C, they need to decline.
Meanwhile, scientists are also worried about a rise in levels of methane, which has a far more potent warming effect than CO2.
The rise is so far unexplained. But one feared source is melting Arctic permafrost, which could eventually release billions of tonnes of carbon dioxide.
See the rest of the story at Business Insider