[By Joe Uehlein and Jeremy Brecher]

In 1940, as Nazi armies marched across Europe, United Automobile Workers Union (UAW) president Walter Reuther made a stunning proposal: Retool the Depression-ravaged auto industry to build 500 planes a year for national defense.  Many scoffed.  But a huge wartime mobilization put tens of millions of unemployed and underemployed workers to work producing what the war effort required, while shutting down wasteful and unnecessary production that would detract from it.

This May, the level of carbon dioxide in the earth’s atmosphere  reached 400 parts per million (ppm) for the first time in human history.

Burning of fossil fuels has led to an increase in carbon and other heat-trapping greenhouse gasses of more than 40% since the industrial revolution.  The atmosphere had this level of carbon three million years ago.  Not surprisingly, the earth was much hotter, the ice caps much smaller, and sea level more than 60 feet higher.

What does this mean for American workers and the leaders of America’s trade unions?  If we continue pouring the greenhouse gasses that cause global warming into the atmosphere at our present rate, we will pass the 450 ppm level in a couple of decades.  America’s workers and workplaces will be devastated along with the rest of our people and the rest of the world.

We can already see the early stages of that devastation.  The giant reinsurance company Munich Re, which has gathered the world’s most comprehensive database of natural disasters, concludes that worldwide, “Floods have more than tripled since 1980, and windstorm natural catastrophes more than doubled, with particularly heavy losses from Atlantic hurricanes.  This rise can only be explained by global warming.”

Floods, fires, droughts, and storms related to climate change are devastating not only to health and the environment, but also the US economy. Superstorm Sandy alone caused an estimated $80 billion in damage. The drought that affected 80% of US farmland last summer destroyed a quarter of the US corn crop, stalled transportation on the Mississippi River, raised food and energy prices nationwide, and did at least $20 billion damage to the economy.

What does all this have to do with jobs?  Consider Sandy.  According to Mark Zandi, the Chief Economist of Moody’s Analytic’s: “Superstorm Sandy wreaked havoc on the job market in November, slicing an estimated 86,000 jobs from payrolls.”  What kind of jobs?  “The manufacturing, retailing, leisure and hospitality, and temporary help industries were hit particularly hard by the storm.”

But isn’t that kind of job loss just temporary?  Consider hurricane Katrina.  In 2004 the New Orleans region had 671,000 jobs.  Katrina wiped out 129,000 of them “” about twenty percent.  In 2011, the region had 90,000 fewer jobs than on the eve of Katrina.

The economic threat of climate change isn’t limited to hurricanes.  Heat waves increase energy costs and cause droughts, which kill crops and increase food prices.  Floods destroy houses, businesses, and infrastructure.  Closed businesses and lost earnings represent an economic loss that can never be recovered.  The devastating health effects of extreme weather like heat waves and floods not only harm individuals but represent a cost for the whole economy.

These impacts will affect unions and workers in every sector of the economy.  In the public sector, for example, local and state governments are already finding their budgets savaged by the costs associated with wildfires, floods, droughts, and sea level rise.  In healthcare, resources will be drained to deal with new the effects of heat waves and new disease vectors.  Ports and airports will be devastated by rising sea levels and storm-related flooding.  Agriculture will be hurt in some areas by drought, in others by flood, as the complex consequences of climate change play themselves out.

The 400 ppm threshold is just as real a warning of threat ahead as the Nazi transgression of national borders in Europe in 1941. And we need just as serious a mobilization to deal with it.  It presents union leaders with the opportunity to take a page from Walter Reuther’s book and propose a dramatic response to climate change that will also transform the opportunities open to American workers.

It is often forgotten that in 1941 the US was in the midst of a great debate in which many denied the reality of the Nazi threat and urged that the US simply stand aloof from the impending global conflagration.  Hitler’s apologists reassured Americans that distant Nazi armies were no threat to them.  But some Americans were wide awake to the threat “” and promoted a strategy to retool our economy to meet it.

Today, we need to stop listening to the blandishments of the fossil fuel industry that spends millions of dollars persuading us that we have nothing to fear from global warming.  We need to rapidly and radically curtail fossil fuel use and halt the race to 450 ppm or even more.  In its place we need an all-out mobilization to eliminate energy waste and replace fossil fuels with climate-safe energy — to begin the long walk back to the 350 ppm limit climate scientists say is safe.

It’s time for labor again to take the lead.