Five party leaders took part in Channel 4's climate debate.
Two other leaders, Boris Johnson and Nigel Farage were invited but chose not to take part. They were replaced by melting ice sculptures.
Reality Check has been looking at some of the claims made in the debate.
Claim: Jeremy Corbyn said "We have the lowest level of tree cover of almost any country in Europe."
Reality Check: The Labour leader made this claim while talking about his party's plans to plant 2 billion trees by 2040 - something we've looked at in a separate piece.
13% of the UK is covered by trees which is well below the European Union (EU) average of more than 30%.
A few European countries have even lower levels of tree coverage: Ireland has 11% and Malta has almost none.
Claim: SNP leader Nicola Sturgeon said "Scotland is already leading the way, we have almost halved our emissions."
Reality Check: That claim was supported by Scottish government statistics in 2018 that showed levels in 2016 were 49% below the 1990 baseline, following a 10.3% drop on the previous year.
Much of that year's drop was attributed to the 2016 closure of the Longannet power station.
But more recent figures showed that by 2017 emissions were 47% down from 1990.
Claim: Liberal Democrats leader Jo Swinson said "We need to make sure that now we have a target for all new-build homes to be zero carbon and to have those high standards. And the Conservatives who can't be bothered to turn up tonight scrapped those plans."
Reality Check: Plans to make all UK homes zero-carbon were first proposed by Gordon Brown in 2006, and cancelled by the Conservative government in 2015.
Zero-carbon homes have better energy efficiency standards and generate all the energy they need onsite through things like solar panels.
The justification for the move was to reduce regulations on housebuilders, which would have made it harder for the government to meet its targets for home construction.
Conservative Viscount Younger of Leckie said in 2015: "research has shown that the zero-carbon standard would have placed a significant regulatory burden on housebuilders and developers."
The following year, the Mayor of London put in place a zero carbon standard for homes in the city.
The Conservative Party has included a pledge to build "environmentally-friendly homes" in its 2019 manifesto.
Claim: Adam Price said "It's an absolute myth actually that the IPCC report was somehow advocating moving away from meat and milk."
Reality Check: The Plaid Cymru leader made this claim when asked by the Channel 4 presenter Krishnan Guru-Murthy whether he was prepared to tell sheep and cattle farmers in Wales that people would have to eat less meat to help the environment. He said no.
A report by the Intergovernmental Panel on Climate Change (IPCC) in August 2019 does not explicitly advise people to stop eating meat and drinking milk.
But it does say: "Consumption of healthy and sustainable diets presents major opportunities for reducing GHG (greenhouse gas) emissions.
Examples of healthy and sustainable diets are high in coarse grains, pulses, fruits and vegetables, and nuts and low in energy-intensive animal-sourced and discretionary foods (such as sugary beverages)."
Claim: Green Party co-leader Sian Berry said reducing the amount of flying: "does mean targeting those 15% of people who take 70% of all flights".
Reality Check: That figure is based on analysis of a government survey (carried out in 2014) by a group calling for a frequent flyer levy.
It found that 52% of people surveyed had taken no flights in the previous year, 22% had taken one, 11% had taken two and 15% had taken three or more.
The Department for Transport's published figures do not break down far enough to confirm the claim, but researchers from Full Fact spoke to the department, which confirmed that a more detailed breakdown of responses suggested those 15% of flyers made 70% of the total flights.