Some 600 organizations have sent a letter to Congress outlining their vision of a Green New Deal. The letter asserts that "we must act aggressively and quickly" to address the problem of man-made climate change, which the letter declares to be the "gravest environmental crisis humanity has ever faced." Surely you'd think that this coalition would advocate doing whatever it takes to ameliorate the "urgent threat" posed by global warming, but you'd be wrong.

The letter's signatories demand that Congress pass legislation mandating that the U.S. shift to 100 percent renewable electric power generation by 2035 or earlier. In addition, Congress must adopt legislation "encouraging public and community ownership over power infrastructure and electricity choice" and also make sure that our "distributed energy systems…are democratically governed."

The letter's signatories then, however, insist that "any definition of renewable energy must also exclude all combustion-based power generation, nuclear, biomass energy, large scale hydro and waste-to-energy technologies." Furthermore, the coalition opposes "market-based mechanisms and technology options such as carbon and emissions trading and offsets, carbon capture and storage, nuclear power, waste-to-energy and biomass energy." Basically, the only acceptable energy is electricity produced by wind or solar power.

A tweet by University of Colorado political scientist Roger Pielke Jr. sums up the self-defeating irrationality of their demands well.

Let's focus on nuclear power. In Science last week, the team of researchers behind the recent MIT report, The Future of Nuclear Energy in a Carbon-Constrained World, pointed out that the most effective and least costly path toward the sort of massive cuts in carbon dioxide emissions being advocated by Green New Dealers is a combination of variable renewable energy technologies and nuclear power.

"Nuclear energy is one low-carbon dispatchable option that is virtually unlimited and available now," the MIT researchers argue. "Excluding nuclear power could double or triple the average cost of electricity for deep decarbonization scenarios because of the enormous overcapacity of solar energy, wind energy, and batteries that would be required to meet demand in the absence of a dispatchable low-carbon energy source."

They recognize that the costs of nuclear power plants have escalated, but suggest that there are ways to rein in costs in the future.

Cynics among us might suspect that the Green New Dealers, by excluding market mechanisms and nuclear power as part of the portfolio of options for addressing the problem of global warming, are not irrational, but are using climate change as an excuse to pursue other social and economic goals.