The message came as campaigners target coal at the UN climate summit
German astronaut urges action on climate change
A commander of the International Space Station says he has seen the impact of climate change on Earth and hopes nations can work together to tackle it on the first day of Cop24.
Addressing delegates at the UN climate conference, astronaut Alexander Gerst said in a video posted Tuesday that he has seen from space the planet's "beauty, its fragility and also the impact humans make".
The German geophysicist and astronaut said he was struck by how brown and dried out Europe looked this summer, which saw extended heat and little rain across much of the continent.
He urged countries that have signed the 2015 Paris climate accord "to turn those words into action and achieve the agreement's goals".
Mr Gerst added he hoped negotiators gathered in Poland would be inspired by the same "spirit of collaboration" that exists on the space station.
Representative from 195 countries are expected to gather in Poland to follow up on the Paris Agreement, which saw all the signatories agree to reduce climate change to less than 2 degrees by 2050.
But a UN body warned last month that the gap between greenhouse gas emissions and levels needed to hit the Paris targets was bigger than ever before.
Air pollution alone is now estimated to kill as many as nine million people every year.
Campaign groups representing citizens from across the world demanded Tuesday that big energy leaves coal in the ground as Cop24 host Poland pushed for protections allowing it to continue burning fossil fuel.
With nations locked in UN climate talks aimed at heading off runaway global warming, many parts of the world are already dealing with the storms, floods, fires and droughts our heating planet will suffer.
Man-made emissions have increased annually since the landmark 2015 Paris climate accord was struck and with political progress slowing, people who will bear the biggest burden issued their clearest plea to date: end fossil fuels now.
"The urgency of the climate crisis is very real on the ground because our people are suffering the different impacts of extreme weather," said Lidy Nacpil, co-coordinator of the Asia Peoples' Movement on Debt and Development.
The UN's independent panel of climate experts in October issued its starkest findings yet: emissions from fossil fuels must be slashed by half within 12 years in order to hit the Paris goals of limited temperature rises.
But most Western economies remain heavily dependent on fossil fuels.
Poland, which gets roughly 80 per cent of its electricity from coal, this week called for nations to weave measures into the UN climate framework that critics fear would allow it to keep polluting for decades.
Polish President Andrzej Duda used his address at the Cop24 opening Monday to say Poland's dependence on coal "does not clash with climate protection and progress achieved in this vein".
Mr Duda reinforced his message on Tuesday with a speech to miners in the southern town of Brzeszcze, where he said he would not allow "anyone to murder Polish mining".
He said while Poland was hosting the climate summit "we're also there to speak the truth without taking into account political correctness, which is often driven by foreign interests and not Polish ones".
Poland and other fossil-fuel reliant economies say they need a gradual and "just transition" towards renewables that protects miners and national energy security.
UN Secretary General Antonio Guterres told officials at negotiations Tuesday that "the dialogue with industries is sometimes difficult and complex".
"But we believe that even in the oil and gas industry, there is a growing conscience that the present trend is not sustainable".