Conservative minister Alok Sharma, who is also the president of Cop26 which begins in Glasgow in November, said the heavy rain sweeping through London and the south-east while he and other politicians were holding preparatory meetings had impressed on them the importance in making real strides to slash emissions.
However, Mr Sharma said he was disappointed the two-day summit with ministers from 50 nations had not made any progress towards a deal to abandon coal power, long hoped for as the lasting legacy of COP26.
The Glasgow conference aims to sign up the world to limit global warming to 1.5 degrees above pre-industrial levels, but without phasing out coal-fired power stations this would be “extremely difficult”, Mr Sharma told a press conference.
The former business secretary said rain and flooding "sweeping London" while ministers were engaged in talks had sharpened their focus.
"I think it is a sober reminder on our own doorstep of the urgency of our task."
On Sunday the UK was deluged with almost a month’s worth of rain in less than 24 hours.
A major incident was declared in several hospitals, tube stations were forced to close and motorists rescued by the emergency services after heavy rain caused sudden flooding throughout London over the weekend.
The flash floods came straight after much of England had baked in the hottest heatwave of the year so far for over a week.
Mr Sharma said the erratic and unseasonal weather should have driven home to delegates gathering for the pre-COP26 meeting the necessity of abandoning fossil fuels to generate power.
But there remained “significant differences” between several nations and no deal could be agreed.
“We weren’t able to get every country in the G20 to agree to language on unabated coal phase-out," said Mr Sharma.
"For me, it is very disappointing and it was very disappointing for those countries who are supportive of this policy."
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