NEW YORK - Global tech giants are falling short on pledges to rein in and combat climate misinformation on their platforms, according to a new report calling for more political will to act on measures to curb the "spread of lies" that threaten climate action.

Climate Action Against Disinformation (CAAD), a coalition of more than 50 advocacy groups and businesses, released the report on Wednesday as activists and business leaders joined Climate Week NYC, an event held alongside the U.N. General Assembly each year, and leaders laid out green plans at the U.N. chief's Climate Ambition Summit.

"Big Tech is clearly failing to stop the extensive climate misinformation that threatens climate action," said Erika Seiber, climate disinformation spokesperson at Friends of the Earth, an environmental advocacy group.

The report examined the misinformation policies of Meta - the parent company of Facebook and Instagram - Pinterest, TikTok, YouTube - which Google owns - and X, formerly known as Twitter.

The platforms were graded on a set of metrics that included policy content, enforcement, advertising, transparency and privacy.

Of the five platforms, Pinterest fared the best, with a score of 12 out of a possible 21, followed by TikTok with nine, Meta eight, YouTube six and Twitter/X only scoring one.

Seiber said the scores in the report were "unacceptable" and should be a wake-up call for platforms and regulators to take climate misinformation seriously.

Common tactics in the proliferation of online climate-related misinformation include casting doubt on the reliability of green technology or positioning green energy as expensive and helping fuel the cost-of-living crisis.

The report said X lacks "any policy that addresses climate misinformation, any transparency mechanisms, and any proof of effective policy enforcement."

A request for comment generated the standard autoreply from X/Twitter: "Busy now, please check back later."

In contrast, the report called Pinterest an "industry leader" and said the company clearly defined climate misinformation and incorporated it into its policies – while still saying there was a lack of independent research confirming enforcement of its climate-related policies.

A Pinterest spokesperson said the platform was proud of the "industry-leading policies" and added that the company would continue to work with third-party experts, including CAAD, as new trends emerge.

Meta did not immediately respond to a request for comment. TikTok had not offered a comment on the report at the time of publication.

A spokesperson for YouTube said Google's policy explicitly prohibited the monetization of content that denies the existence of climate change, "as well as ads that promote these claims."

The policy, the spokesperson said, means ads that deny the existence or causes of climate change are blocked – pushing back on the report's conclusion that Google's ad policy, "while preventing monetization of climate denial content, does not address climate denial via advertisements themselves."

Watchdog groups have long been tracking the issue.

In June, the wildfire smoke wafting from Canada to locations as far away as New York prompted a surge in the number of posts using the term "climate scam", according to the Center for Countering Digital Hate, a non-profit group.

Questionable narratives about the wildfires and smoke included that breathing in smoke is not harmful to health, climate change does not worsen wildfires, and the wildfires are part of a planned "climate scam", the group found.

Climate change is creating hotter, drier conditions that can lay the groundwork for small fires to escalate into out-of-control blazes, research has found.

One way to combat disinformation when it comes to climate is by being transparent and relying on facts and figures, said Humza Yousaf, first minister of Scotland, an early donor of finance to help developing countries deal with worsening loss and damage from extreme weather and rising seas.

"You can't hide countries ablaze, on fire because of record temperatures and wildfires. You can't hide flooding because of excessive rainfall," he said in an interview after an event at Climate Week NYC.

"So we have to make sure that's being amplified," he added, while saying not everyone will be persuadable.

"I'm not sure we waste too much time on the naysayers, because some people, frankly, we will never convince."

(Reporting by David Sherfinski; Editing by Jon Hemming)