Young people today confront an imminent gathering storm. They have at their command considerable determination, a dog-eared copy of our beleaguered Constitution, and rigorously developed science. The Court must decide if that is enough.
SECTION 1: Climate has always been changing, but humans are now the principal drive for climate change, overwhelming natural climate variability.
a. Rising atmospheric CO2 levels, primarily a result of fossil fuel emissions, have become the predominate cause of continuing climate change. Increasing CO2 is now responsible for about 80 percent of the annual increase in climate forcing by greenhouse gases (GHGs), the other 20 percent being from the combination of CH4 (methane), N2O (nitrous oxide) and other trace gases.
b. Climate change is driven by cumulative CO2 emissions. The United States has contributed a disproportionately large share of cumulative global emissions, and thus the United States is, by far, the nation most responsible for the associated increase in global temperatures.
SECTION 2: Current levels of long-lived atmospheric GHGs, mainly CO2, cause Earth to be out of energy balance. This imbalance, with Earth absorbing more solar energy than it radiates back to space, is driving climate change.
a. Earth’s energy imbalance is now measured and large, consistent with expectations based on physics. As long as Earth remains out of energy balance, more energy coming in than going out, the planet will continue to get hotter.
b. Earth’s energy imbalance is the immediate drive of climate change, which has deleterious climate impacts that are now beginning to emerge. If GHG amounts continue to rise unabated, the energy imbalance will drive global warming to levels with climate impacts beyond the pale, as delineated in OPINION 3.