Big polluters must pay for their role in creating the climate crisis, campaigners said Wednesday as the United Nations hosted its 25th annual Conference of the Parties (COP 25) of the United Nations Framework Convention on Climate Change.

"For decades, big polluters have gone to any lengths to block, weaken, and delay policy," Pascoe Sabido, researcher and campaigner for the Corporate Europe Observatory, said in a statement. "That time is over. They need to pay for the real solutions and be held liable for their years of abuse."

The call to hold corporations accountable came in the wake of reports on the sponsorship of the conference by emissions-spewing corporations, including Spain's largest polluter, the electric power generator Endesa.

As Earther reported, the sponsorship is a good deal for Endesa:

The company paid $2.2 million to be a diamond sponsor of the conference, though they'll receive some of that money back in tax incentives, according to a report from El Periodico. In exchange for their funding, Endesa received an exhibition space in the conference's stakeholder area.

On Tuesday, Observatory of Multinationals in Latin America researcher Erika González wrote for Common Dreams that "sponsorship is a symptom of a larger problem of corporate capture at the UNFCCC."

"Inside the talks, trade associations representing the interests of the fossil fuel industry and other Big Polluters stalk the halls and push their members' agenda," wrote González. "The result of this corporate omnipresence is clear—the negotiations move at a snail's pace and more often than not reflect the interests of global corporations, not people and the planet."

The sponsorship generated accusations of greenwashing from climate advocates on social media.

A prime example of #greenwashing and #impactwashing from @CocaCola at #COP25, a company that is terrible for health and planet but number 1 at pretending to care and confusing the evidence. Important reminder for event organizers to #walkthetalk when accepting sponsorship. https://t.co/yfJolNdG6h — Sofia Condes (@sofiacondes) December 3, 2019

In a statement, Philip Jakpor of Environmental Rights Action said polluters must be held accountable.

"The fossil fuel industry must take full responsibility for the climate change crisis," said Jakpor. "There is no alternative to cutting down emissions at the source and the time is now."