US could reach 'net-zero' carbon by 2050. Here's how.

Key steps must be taken by 2030.

The U.S. can cut its carbon output to zero by the middle of the 21st century, according to a sweeping new Princeton University study. In such a "net-zero" scenario, the American carbon output would be equal to or lesser to the carbon pulled out of the atmosphere on U.S. soil. 

But to get there, the country must start now.

American per-capita carbon emissions are the highest in the world, according to the World Bank, with the country emitting 17.6 tons (16 metric tons) of carbon for ever person in 2016. The U.S. is second only to China in its total contributions to climate change. President-elect Joe Biden campaigned on achieving net-zero emissions by 2050. And according to the Princeton study, that goal is achievable and would even be cheaper than remaining on the economy's current course. But urgent action is needed in the next decade to make it happen.

"We find that each net-zero pathway results in a net increase in energy-sector employment and delivers significant reductions in air pollution, leading to public health benefits that begin immediately in the first decade of the transition," the authors wrote in the report, published Dec. 15 on the Princeton website. "The study also concludes that a successful net-zero transition could be accomplished with annual spending on energy that is comparable or lower as a percentage of GDP to what the nation spends annually on energy today."

There isn't one way to achieve the goal, the authors found. In their model, they tested approaches using only renewable energy and others that relied more heavily on next-generation nuclear technologies (including ones that still produce nuclear waste), carbon capture and natural gas — landing on five possible routes the U.S. might take to a net-zero 2050. But regardless of the route taken, certain steps must be taken before 2030, the authors wrote.

Those include putting 50 million electric cars on the road and 3 million public charging ports, increasing the use of electric heating systems in homes from today's 10% to 23%, tripling the use of electric heating on commercial property, quadrupling wind and solar capacity from today's 150 gigawatts to 600 gigawatts, building high voltage transmission infrastructure to carry renewable energy over long distances and reducing non-carbon dioxide (CO2) greenhouse gas output, nitrous oxide (N20) and methane (CH4), by 10%.

The researchers also called for changing forest and agricultural management practices to increase the amount of carbon permanently removed from the atmosphere by plants each year, developing a pipeline network for moving carbon pulled out of the air to underground storage facilities, and investing in developing power technologies like hydrogen combustion power plants.

17 December 2020

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