Two venues set to host many of the events at the Cop26 climate change summit in Glasgow in November have received some of the worst energy efficiency ratings in the city.
The SEC Armadillo and SEC Centre have received the second-lowest possible grade.
Inspectors have given the venues an energy performance certificate rating of F. The lowest grade is G, with A being the best.
The SEC Centre's owners were told nine years ago to invest in carbon neutral technologies, while authorities at the SEC Armadillo have been advised to introduce new insulation and lighting to reduce the venue's carbon footprint.
Renewable energy sources have not been installed at either site.
The UK government chose the venues, and Glasgow Science Centre, to host the climate summit, which will be attended by leaders from around the world.
Greenpeace told The Scotsman it would be the first climate summit where the rooms themselves would be “one of the elephants in the room”.
It is understood all three venues produce 6,659 tonnes of carbon dioxide a year.
UN guidance for host countries says energy-efficient buildings should be used or energy-reduction measures should be in place.
SEC said all the electricity used at its venues since last February came from renewable sources and that the company was reducing energy and water waste.
“We continuously work to make our buildings more energy efficient and are committed to improving our environmental performance,” a spokesman for SEC told The Scotsman.
“We acknowledge that events can have a substantial impact on the natural and built environment and we are in the advanced stages of developing a sustainability and energy strategy.
“This will consider opportunities to make our venue more sustainable and to identify environmental improvements, innovations and best practices together with a coherent plan for implementation.”
He gave the warning as he planned face-to-face meetings in China, which has committed to climate neutrality by 2060.
This week more than 200 health journals published editorials calling on world leaders to take urgent action on climate change.