By John Kruzel and Andrew Chung
WASHINGTON, Oct 4 (Reuters) - The US Supreme Court begins its new nine-month term on Monday with arguments in a major case involving a bid by oil companies ExxonMobil and Suncor Energy to scuttle a lawsuit by officials in Boulder, Colorado, seeking monetary damages for harms caused by climate change.
It is the first of several important cases already teed up for the term, with disputes involving issues such as President Donald Trump's immigration policies and state-level
bans on assault-style rifles to be heard in the coming months. The court's 6-3 conservative majority has moved US law dramatically rightward in recent years.
The top US judicial body, as is its custom, opens its term on the first Monday in October.
US-based Exxon and Canada-based Suncor appealed after the Colorado Supreme Court let Boulder's lawsuit accusing them of state law violations proceed. The Trump administration has backed Exxon and Suncor, arguing that federal law precludes Boulder's claims.
Boulder's city and county governments have accused the two companies of helping drive climate change and misleading the public about the risks of fossil fuels. Boulder aims to hold the companies liable for past and future costs associated with climate change such as infrastructure repairs, environmental damage, emergency management and harms to public health.
The burning of fossil fuels releases greenhouse gases including carbon dioxide into the atmosphere, trapping heat and raising average global temperatures over time.
Nearly 60 state and local governments have brought similar suits seeking billions of dollars from fossil fuel companies, with more continuing to be filed, Exxon and Suncor told the justices. A ruling by the Supreme Court in favor of the companies could lead to many of those cases being dismissed.
Monday's arguments mark the latest example of energy-sector companies asking the justices to block climate-related liability or limit federal environmental regulation.
Backers of the oil companies argue that if Boulder's most far-reaching claims are allowed to proceed, it could give states sweeping power over conduct occurring far outside their borders.
Energy companies and trade groups, along with states allied with them, have built a largely winning record before the justices over the past two decades in cases involving climate liability and the reach of federal environmental regulation.
Exxon and Suncor argue, among other things, that Boulder's claims intrude on an area governed by the Clean Air Act.
Justice Samuel Alito has recused himself from participating in the case. Alito owns stock in several oil and gas companies but not Exxon or Suncor, according to his financial disclosure forms.
The Supreme Court's decision is expected by the end of June.
(Reporting by John Kruzel and Andrew Chung; Editing by Will Dunham)
