Schoolchildren skipping class to strike and protest - spurned on by Swedish wunderkind Greta Thunberg - bringing city centres to a standstill and sounding warnings to leaders across the world dragged the climate emergency into the mainstream in 2019.
Thunberg - virtually unknown outside of her homeland a year ago but now a global star nominated for a Nobel prize - and millions of young people took part in weekly demonstrations demanding climate action.
The "Extinction Rebellion" movement embarked on a campaign of peaceful civil disobedience that spread worldwide, armed with little more than superglue and the nihilistic motto: "When hope dies, action begins."
The 2015 Paris agreement saw nations commit to limiting global warming to 2C above pre-industrial levels as a way of curbing the worst impacts of global warming.
A safer cap of 1.5C was included as a goal for nations to work towards.
With earth having already warmed by 1C, the United Nations Intergovernmental Panel on Climate Change (IPCC) dropped a bombshell late last year.
Its landmark report in October 2018 laid the groundwork for the string of climate shockwaves that rumbled throughout 2019: the world is way off course for 1.5C, and the difference between 1.5C and 2C could be catastrophic.
'12 years to act'
For Corinne Le Quere, president of France's High Commission for Climate Change and member of Britain's Committee on Climate Change, 2019 was "something new".
"I've worked on climate change for 30 years and for 29 of those, as scientists, we've worked unnoticed," she told AFP.
The IPCC report concluded that global CO2 emissions must drop 45% by 2030 - and reach "net zero" by 2050 - to cap temperature rise at 1.5C.
"It's given us a clear timeline: we have 12 years to act," said Caroline Merner, 24, a Canadian member of the Youth4Climate movement.
But while society and particularly younger generations appear to have woken up to the threat of climate catastrophe, industry shows little signs of sharing their urgency.
Cyclone Idai, Typhoon Hagibis
Greenhouse gas emissions are once again set to rise in 2019 after hitting a record in 2018, as extreme weather events - made more likely as the planet warms - struck seemingly everywhere this year.
Cyclone Idai in Mozambique, typhoon Hagibis in Japan, a deadly, record-breaking heatwave across much of Europe, wildfires in California and eastern Australia, floods in Venice... the list goes on.
The threat posed by climate change became so stark in 2019 that Indonesia, one of the fastest-growing economies on Earth, decided to move its capital to somewhere that wasn't sinking.
Faced with an unbreachable body of evidence and mounting pressure from the streets, governments in 2019 started, slowly, to mobilise.
A total of 66 nations now have plans to be carbon-neutral by 2050.
The cities of London and Paris declared official ecological and climate emergencies.