“I would feel relief and joy, that what we’re doing matters,” mentioned 18-year-old Kian Tanner, “that when we speak out, when we create action, we can create positive change in the world.”

The stress between the 2 sides was particularly obvious whereas the protection was cross-examining the plaintiffs’ skilled witnesses, making an attempt to show that any answer would must be far larger than Montana may present.

“If Montana just stopped emitting CO₂ today, if every farmer threw in the keys to their tractors, if I even handed you my keys, would you agree that would not have an impact on local GHC, I mean GHG [greenhouse gases]?” requested Assistant Attorney General Thane Johnson, who repeatedly blended up acronyms through the trial.

“That would be a good step forward in trying to bring the climate system into equilibrium,” responded Cathy Whitlock, a paleoclimatologist and lead writer of the 2017 Montana Climate Assessment.

The attorneys requested an analogous query of Steven Running, a local weather scientist and member of the group that received the Nobel Peace Prize for the 2007 IPCC report: If Montana stopped emitting greenhouse gases, would that stop the plaintiffs from being harmed by local weather change?

“We can’t tell. What’s been shown in history over and over is that when a significant social movement is needed, it’s often started by one or two people,” mentioned Running, who lives in Missoula. “If our state did this, we can’t tell how many other states would decide ‘That’s the right thing to do, and we’re going to do it too.’ ”

In her written skilled report for the protection, Judith Curry, a climatologist who disputes the scientific consensus that human exercise is the first driver of local weather change, argued that the plaintiffs’ considerations about local weather change are enormously exaggerated and that emissions from fossil fuels generated in Montana are minuscule in comparison with international emissions and don’t immediately affect Montana’s climate and local weather. However, as Curry wrote on her website, on the fourth day of the trial she obtained a name from the state’s legal professionals saying they had been “letting [her] off the hook.” She didn’t testify, and her report was not entered into proof.

Before Curry’s testimony was canceled, Peter Erickson, a local weather coverage skilled who makes a speciality of climate-related emissions accounting, responded to Curry’s written report throughout his testimony. “You can’t say an individual source [of CO₂] isn’t important because the problem is so big. To say that says more about the size of the problem than to say anything meaningful about the action,” mentioned Erickson. “Montana’s contribution [to greenhouse gas emissions] is nationally and globally significant. What Montana does matters.”

On day 5 of the plaintiffs’ case, vitality transition skilled Peter Jacobson advised the choose {that a} speedy transition to renewable vitality was technically and economically possible for Montana, however the transfer to wind, water, and photo voltaic vitality should occur at a a lot quicker tempo than is at the moment the case.

“The main barrier to energy transition is that we need collective willpower,” he mentioned. “That requires individuals, state governments, and national governments to work toward this goal.”