MADRID On the morning of Dec. 2, a bizarre sight several national newspapers with nearly identical front pages covered newsstands around Spains capital city.

Endesa presents its solutions for an emission-free society at COP25, read the cover of El Pas on the day that thousands of delegates, scientists and environmentalists flocked to the opening day of the United Nations climate conference. At least seven other influential publications carried similar full front-page advertisements from Endesa, Spains largest electric utility, all with the same photo of an electric car charging station.

Endesa is also the biggest emitter of greenhouse gases in Spain, accounting for approximately 9% of the nations planet-warming emissions.

Along with its enormous newspaper ad buy, the company paid more than $2 million to be a top-level sponsor of the 2019 U.N. climate talks. It hosted official events at its nearby headquarters, where outside it displayed a giant banner that read this canvas absorbs the same CO2 as 182 trees. Endesas engagement with the summit reflected its commitment to the process of ecological transition and the fight against climate change, the company wrote on its website .

Endesa isnt the only company with ties to fossil fuels that had an outsize presence at the Madrid talks. Corporate Accountability and several other watchdog groups published a research paper last month on the corporations that bankrolled the conference, a list that also included Iberdrola, a Spanish energy company and one of the countrys top 10 emitters; Santander, Spains largest bank and a major financier of coal production in Poland; and Acciona, a renewable energy and infrastructure giant that until recently touted on its website its help constructing 75% of Spains natural gas storage capacity. (An Acciona company spokesperson told HuffPost that the web page, which has since been taken down, was outdated, and that the company is no longer involved as a contractor of oil and gas projects.)

Spain stepped in to host the 25th Conference of the Parties, or COP25, in October after Chile backed out due to civil unrest across the country. With just two months to organize the massive event, the Spanish government courted some of the nations biggest corporations, El Periodico reported . As top-tier diamond sponsors, Endesa and Iberdrola each dished out $2.2 million in exchange for tax breaks of up to 90% of their contribution. Sponsors also received exhibit space in the summits Green Zone, an area where businesses and other stakeholders showcased their work and new technologies.

Industry presence at U.N. climate talks is nothing new. The 2018 summit in Polands coal capital of Katowice was sponsored by three of the countrys largest coal producers, as well as several European oil and gas companies.

But watchdogs and climate activists say it is unacceptable that, as scientists around the globe are warning that we are rapidly running out of time to prevent catastrophic warming, the industry most responsible for driving the crisis is allowed access to the very forum where world leaders are supposed to be striking deals to address the problem. They liken the situation to giving cigarette companies a seat at global talks on mitigating lung cancer and say industry interference in the U.N. process is a big reason world governments have failed year after year to put in place measures that significantly curb emissions.

A growing number of developing nations and advocacy groups argue that if parties to the United Nations Framework Convention on Climate Change, or UNFCCC, ever want to make real progress, they must take a page out of the international tobacco treaty.