Climate scientists have long warned of severe impacts on the near horizon, and the 21st century has seen more than a few natural disasters made worse or more likely by global warming.
But a cascade of deadly extreme weather this summer could make 2021 the year when climate predictions became a reality that can no longer be ignored.
Ahead of next week's IPCC meeting, here's a recap, from Death Valley-like temperatures in Canada to rain-filled subway cars in central China with parents lifting their children above the waterline.
Canada's heat dome
In late June, western Canada was caught under a "heat dome", a phenomenon causing scorching temperatures when hot air is trapped by high pressure fronts, and heats up even more as it is pushed back down.
The country broke its record high temperature several times, finally capping at 49.6 degrees Celsius (121 degrees Fahrenheit) in the village of Lytton on June 30.
The US states of Washington and Oregon were also affected.
The exact human toll is not yet known but amounts to at least several hundred deaths.
A study by a group of leading climate scientists found that the weather conditions would have been "virtually impossible" without human-caused climate change.
The World Weather Attribution group said global warming, caused by greenhouse gas emissions, made the June heat wave at least 150 times more likely to happen.
Deadly floods in Europe
In mid-July western Europe was hit by devastating floods after torrential rains that ravaged entire villages and left at least 209 people dead in Germany and Belgium, as well as dozens missing.
The flooding also caused damage in Luxembourg, the Netherlands and Switzerland.
Up to two months' worth of rainfall came down in two days in some parts of the region, waterlogging soil that was already near saturation.
Deluge in China
Flooding also hit China this month, with cars strewn across the central city of Zhengzhou on Thursday as shocked residents picked through the debris of a historic deluge that has claimed at least 33 lives.
An unprecedented downpour dumped a year's worth of rain in just three days on the city, instantly overwhelming drains and sending torrents of muddy water through streets, road tunnels and the subway system.
California's raging wildfires
Triggered by an alarming drought, the wildfire season is just starting in the American West where thousands of firefighters are already dealing with 80 large blazes.
By the beginning of the week the fires had ravaged more than 4,700 square kilometres (1,800 square miles) of vegetation.
The most spectacular blaze is the "Bootleg Fire" in Oregon, which in the space of two weeks has burned the equivalent of the city of Los Angeles in vegetation and forests.
Marcus Kauffman, a specialist with the Oregon forestry department, said the blaze "feeds on itself" and has even been causing its own lightning.
In neighbouring California, several villages were evacuated in the face of the advancing "Dixie Fire", which is suspected to have been caused by a tree falling on power cables.