Analysis pinpoints US emissions cuts needed for 1.5 degrees C of global warming

With the U.S. set to ratchet up its commitment under the Paris Agreement on climate change, an independent tracking group has released a new estimate that the nation needs to cut its emissions by more than half over the next decade to avoid the worst effects of climate change.

According to a March 11 analysis by the Climate Action Tracker, the U.S. must aim to cut economywide emissions by between 57% and 63% by 2030 relative to 2005 levels for its nationally determined contribution, or NDC, to line up with a 1.5-degree C warming scenario.

The Paris deal aims to limit warming at the end of this century to well below 2 degrees C measured against preindustrial levels, with signatories agreeing to strive for a 1.5-degree C goal. The latest United Nations special report on climate change found that the world needs to cut its planet-warming emissions roughly in half by 2030 and hit net-zero by 2050 to have a good chance of limiting warming to that lower target.

The March 11 analysis was released the same day White House National Climate Adviser Gina McCarthy said the U.S. is preparing to announce a new NDC next month that aligns with President Joe Biden's goal of decarbonizing the U.S. power sector by 2035. McCarthy's counterpart, Presidential Envoy for Climate John Kerry, also said last week that the U.S. plans to urge the world's top emitters to commit to new targets that reflect 1.5 degrees C of warming.

In 2015, the U.S. submitted a nonbinding pledge to cut its emissions by between 26% and 28% by 2025 relative to 2005 levels as part of the original Paris accord. But climate scientists have warned that the deal's initial NDCs are likely to produce up to 3.7 degrees C of warming by the end of the century. And a recent report released ahead of a United Nations climate summit this fall found that new or strengthened NDCs covering about 30% of the world's heat-trapping emissions would only reduce those emissions 0.5% from 2010 levels by 2030.

With specific figures for a new U.S. NDC still under wraps, the Climate Action Tracker's analysis looked at Biden's plans for three sectors: power, transportation and buildings.

The analysis found that Biden's net-zero-by-2035 goal for the U.S. electricity grid is consistent with the goals of the Paris agreement but concluded that "there is still a long way to go" on transportation. To stay within 1.5 degrees C of warming, the analysis said between 95% and 100% of sales of new light-duty vehicles in the U.S. should be emissions-free by 2030.

In addition, the analysis estimated the U.S. buildings sector needs to reduce its carbon footprint 60% by 2030, a more stringent target than Biden's current plan to cut building emissions by 50% by 2035.

The Climate Action Tracker's analysis excluded the effects of land use, land-use change and forestry.