Youth plaintiffs alleging that the federal government failed to protect them against climate change impacts are asking the US Supreme Court to overrule a lower court's decision to toss the longstanding case.

In their Sept. 12 petition to the high court, the 21 youths in Juliana v. United States argued that the US 9th Court of Appeals in May erred when it granted the US Justice Department a rarely invoked emergency measure to halt the case. The petition said the government repeatedly asked for a "writ for mandamus" to avoid hearing the nine-year-old case. The measure is used when a party to a lawsuit has no other remedy than to seek action from a higher court because it believes the lower court did not follow the law.

"When the government is defending against a suit it believes will have significant consequences if plaintiffs prevail on the merits, can it repeatedly pursue mandamus before final judgment as a 'get out of the case free' card merely to avoid the cost of litigation — until it draws the right three-judge panel?" the youths asked.

With the US government a defendant in nearly one-fifth of civil cases filed in federal court, the youths said "any escalation of this strategy by the Department of Justice could easily glut the appellate courts with meritless petitions." The youths are now asking the Supreme Court to issue a writ for mandamus of its own to revive the lawsuit.

Several other pending youth climate cases are targeting alleged state inaction on climate change rather than going after the federal government. The exception is a 2023 lawsuit 18 California children filed against the US Environmental Protection Agency.

In addition to the youths' cases, states have filed a flurry of lawsuits in recent years that are now moving through the courts. The cases target Exxon Mobil Corp. BP PLC, Shell PLC and other oil industry players and focus mainly on alleged violations of state consumer protection and public nuisance statutes.

Climate lawsuits have proliferated worldwide since 2015 when the Paris Agreement on climate change was adopted, peaking in 2021 when over 250 suits were filed, according to a recent report by S&P Global Ratings. While such lawsuits have spread beyond US borders, nearly 70% of cases filed originated in the US, the analysis said.

"Not only the geographic split is changing, but so is the sectoral split and even the type of defendant," Tommy Englerth, an associate director of sustainable finance with S&P Global Ratings, said during a Sept. 12 webinar discussing the study. "There's been a notable shift towards other industries as well. The number of cases filed against financial institutions, utility companies, manufacturing companies, even leisure companies and others, appears to be growing nominally."

At the same time, Englerth noted, some climate lawsuits are now naming executives and directors as defendants. Englerth said some cases are also bucking the trend and challenging corporate efforts to reduce emissions. Although the number of new lawsuits has dipped since 2021, the annual volume of new cases will likely remain high, the S&P Global Ratings analysis predicted.