There have been two, maybe three, landmark heat waves in the history of man-made global warming. The first was in 1988. Then as now, the eastern two-thirds of the United States was broiling while relentless drought parched soil and withered crops across the Midwest. But in Washington, the underlying problem was being named for the first time. On June 23, NASA scientist James Hansen testified to the Senate that man-made global warming had begun. The New York Times reported his remarks on Page 1, and the rest of the media at home and abroad followed suit. By year’s end, “global warming” had become a common phrase in news bureaus, government ministries and living rooms around the world.

The second landmark heat wave occurred in 2003. It escaped many Americans’ notice because it took place in Europe, which suffered the hottest summer on record. By August, corpses were piling up outside morgues in Paris. Initial estimates suggested a death toll of 15,000. But a comprehensive study by the European Union later concluded that, in fact, there had been 71,449 excess deaths.

As 1988 had done in the United States, the 2003 heat wave transformed the conversation about climate change in Europe. David King, the science adviser to the British government, called climate change “the most severe problem we are facing today, more serious even than the threat of terrorism.” King cited the finding, reported in Nature, that global warming had been responsible for about half of the excessive temperatures of 2003. It was a historic breakthrough—the first time scientists were able to attribute a carbon fingerprint to a specific weather event. King’s advocacy led Prime Minister Tony Blair and other European leaders to endorse stronger action and to press the Bush administration to do the same.

And the third landmark heat wave? It’s very possible we’re living through it right now. Summer 2012 has broken thousands of records, bringing misery and worse to millions of Americans. By mid-July the death toll was nearing 100, said Wunderground.com. That is certain to rise—not just because the forecast is for hot weather to persist but because, as in 2003, many heat wave deaths are epidemiologically traceable only well after the fact. Meanwhile, the United States is suffering the worst drought in fifty years, leading the Department of Agriculture to declare more than 1,000 counties—about one of every three in the nation—natural disaster zones. The reverberations will be global and may include violence. “Corn and soyabean prices surged to record highs [on July 19], surpassing the peaks of the 2007–08 crisis that sparked food riots in more than 30 countries,” said the Financial Times.

By no means is the United States the only place enduring brutal temperatures. NASA scientists were so shocked by how much of Greenland’s ice cover has melted this summer that they suspected their data was mistaken. But no. Double-checking revealed that 97 percent of Greenland’s ice cover thawed during July, melting faster than at any time since 1889. One scientist noted that such extensive melting has occurred roughly once every 150 years over the course of Greenland’s long-term history, so the current melting could be a manifestation of that pattern. That is small comfort, however, given that such natural melt cycles are now being super-charged by the vast amount of additional greenhouse gases that humanity has pumped into the atmosphere.

Handout images provided by NASA show the extent of surface melt over Greenland’s ice sheet on July 8, left, and July 12, right. (AP Photo/Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory)

But meteorological conditions alone do not determine whether a given heat wave is a global warming landmark; a shift in public awareness and political response is required as well. And it remains very much an open question whether 2012 will qualify. Certainly neither of the main presidential candidates is providing leadership. Nobody expects it of Mitt Romney, who sang the Tea Party tune on climate science during the Republican primaries only to claim he isn’t a denier now that he faces a general electorate. But President Obama is the great disappointment. In an April interview with Rolling Stone, he said he’d make climate change a campaign issue, but he has been shamefully silent as the heat wave dominates headlines. Yes, he expressed sympathy for the victims of Colorado’s wildfires, but he appears to have said not a word about what is fueling these disasters, even though his administration’s scientists have said global warming is partly to blame. His cabinet has been equally reticent. Agriculture Secretary Tom Vilsack repeatedly declined to comment when reporters asked whether global warming was contributing to the weather devastating the Farm Belt. It’s hard to solve a problem if you’re not willing to name it.

Actually, Obama has been worse than silent. Instead of championing—and fighting for—an ambitious program for a green economic revival, he has buckled to pressure from a fossil fuel industry that dismisses any attempt to protect the environment as a “job-killer.” The president has gone out of his way to promote increased drilling for oil and natural gas, including in the Arctic—which, ironically, is more accessible now because of the global warming caused by burning fossil fuels. Shell Oil wants to begin exploratory drilling in the region in August, despite the Arctic’s extreme weather and remote location, which would make containing an oil spill extremely difficult, as Coast Guard Commandant Robert Papp has told Congress. Does no one in the Obama administration remember that it was just such an exploratory rig in the Gulf of Mexico in 2010 that caused the worst environmental disaster in our nation’s history?

There is still time to trigger the reaction that would make the 2012 heat wave a landmark event, but the impetus will have to come from mobilized citizens. Activists with the End Fossil Fuel Subsidies campaign are planning to bird-dog Congressional candidates in swing districts. They’ll ask them if they support the End Polluter Welfare Act, which seeks to end the $11 billion subsidy that taxpayers give the richest industry in history every year. Greenpeace and the Alaska Wilderness League are spearheading opposition to Shell’s drilling in the Arctic. The newly formed group Climate Parents hopes to give voice to the most underorganized constituency on this issue—parents—by arguing that protecting one’s child from climate change is now as much a part of a parent’s job as providing proper food, clothing and shelter (disclosure: I’m a co-founder). It’s time to make things as hot and uncomfortable for the planet-wreckers as they’ve made summer 2012 for all of us.