There have been two, maybe three, landmark heat waves in the history of man-made global warming. The first was in 1988 and it put the concept of global warming on the map. Then as now, the eastern two-thirds of the United States broiled beneath ferociously high temperatures, while relentless drought parched soil and withered crops across the Midwestern farm belt.
But in Washington, the underlying problem was being named for the first time. On June 23, NASA scientist James Hansen testified to the US Senate that man-made global warming had begun. The New York Times reported his remarks on page one; the media at home and abroad followed suit. By year's end, "global warming" had become a common phrase in news bureaux, 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, where it was the hottest on record. By August, corpses were piling up outside morgues in Paris. Initial estimates suggested a death toll of 35,000 people across the continent. But a comprehensive study by the European Union later concluded that, in fact, there had been 71,449 excess deaths in the space of six weeks - far more than the number of US dead during the entire Vietnam War.
As in 1988, the 2003 heat wave transformed the political conversation about climate change. David King, the science adviser to the British government, began speaking out more forcefully, calling climate change "the most severe problem we are facing today, more serious even than the threat of terrorism".
King cited the finding of British scientists, reported in Nature, that global warming had been responsible for "about half" of the excess temperatures of 2003. It was an 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 actions against global warming and to press the George W Bush administration to do the same.
Landmark heat wave
And the third landmark heat wave? It's very possible we're living through it right now. Summer 2012 has broken thousands of records in the US, bringing misery and worse to millions. The nation is suffering the worst drought in 50 years, leading the US Department of Agriculture to declare 1,000 counties - one of every three in the nation - natural disaster zones. "It's like farming in hell," Fred Below, a plant biologist at the University of Illinois Urbana-Champaign, told Bloomberg Businessweek.
Because the US is the world's leading agricultural exporter, the reverberations will be global and may include violence. "Corn and soybean prices surged to record highs [in July], surpassing the peaks of the 2007-08 crisis that sparked food riots in more than 30 countries," the Financial Times reported. According to the Christian Science Monitor, street clashes have already occurred in Indonesia, where soybeans are used to make tofu, the main protein source for the nation's poor.
By no means is the US the only place enduring brutal temperatures this summer. Last week, more than 450 million Indians were left without electricity after a massive power blackout. Record high temperatures had caused air conditioning use - and therefore electricity demand - to soar, overloading the nation's power grid.
Meanwhile, Greenland's ice has melted so quickly and extensively this summer that shocked NASA scientists initially suspected their data was mistaken. But no. Double-checking revealed that 97 per cent of Greenland's ice cover thawed during July, melting faster than at any time since 1889.
But meteorological conditions alone do not determine whether a given heat wave qualifies as a global warming landmark; a shift in both public awareness and political response is required as well. And it remains very much an open question whether, on these grounds, the 2012 heat wave will qualify as a landmark event.
Certainly neither of the major US presidential candidates is providing leadership. True, nobody expects it of Mitt Romney, who sang the Tea Party tune of denying climate science to win the Republican primaries - only to claim that he isn't a denier now that he faces a more centrist electorate.
As usual, President Obama is the greater disappointment, if only because he knows better. In an April interview with Rolling Stone, Obama pledged to make climate change an issue in the 2012 campaign, but he has been shamefully silent as the current heat wave unfolds. Yes, he expressed sympathy for victims of Colorado's wildfires, as presidents invariably do after such disasters.
But Obama appears to have said not a word about what is fuelling these disasters, even though his own government's scientists have said that global warming is partly to blame. His Cabinet members have been equally reticent. Agriculture Secretary Thomas Vilsack repeatedly declined to comment when reporters asked whether global warming was contributing to the weather devastating the Farm Belt. How can you solve a problem if you're afraid to name it?
Climate change diplomacy
Actually, Obama has been worse than silent. Instead of championing and fighting for an ambitious programme for a green economic revival, he has buckled to pressure from opponents who dismiss any attempt to protect the environment as a "job killer". And he has gone out of his way to promote increased drilling for oil and natural gas, including in the Arctic - which, ironically, is now more accessible precisely because of the global warming caused by burning fossil fuels.
Shell Oil wants to begin exploratory drilling in the Arctic this month, even though the region's extreme weather and remote location would make containing any oil spill extremely difficult, as US 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 US history?
Adding insult to injury, Obama's chief climate negotiator last week appeared to abandon a cornerstone of climate change diplomacy: the goal of limiting average global temperature rise to two degree Celsius above the level that prevailed before the Industrial Revolution.
Todd Stern, speaking at Dartmouth College, argued that retaining the two degree target, which was affirmed by the international community at the Copenhagen climate summit in 2009 and again at the Doha summit in 2011, "will only lead to deadlock" on the part of negotiators. "It is more important to start now with a regime that can get us going in the right direction," said Stern, whose remarks were criticised in official statements from the European Union, the Alliance of Small Island States and many NGOs.
With much of the summer still ahead, there remains time to trigger the political reaction needed to make the 2012 heat wave a landmark event, but the impetus evidently will have to come from organised citizens rather than mainstream politicians and media outlets. In the US, author and activist Bill McKibben has published a major article in Rolling Stone, explaining that fossil fuel companies now control underground reserves five times greater than can be burned if the two degree Celsius target is to be respected.
To keep as much of that carbon in the ground as possible, McKibben and his advocacy group 350.org are stepping up grassroots protests against tar sands and natural gas fracking in the short-term, while contemplating in the longer term a divestment campaign against fossil fuel companies akin to the campaign that helped bring down apartheid in South Africa in the 1980s.
Meanwhile, activists with the End Fossil Fuel Subsidies network plan to bird-dog swing district congressional candidates as the November elections approach. The activists will ask whether the candidates support cancelling the $11bn a year US taxpayers currently give to fossil fuel companies, as mandated in the End Polluter Welfare Act sponsored by Representative Keith Ellison of Minnesota and Senator Bernie Sanders of Vermont.
A crisis, they say, is a terrible thing to waste, and that certainly holds true for the brutal summer of 2012. But only by speaking the language that power respects - by shunning corporations that oppose climate action and removing from office politicians who do their bidding - can citizens make the difference necessary. It's time to make things as hot and uncomfortable for the planet wreckers as they have made summer 2012 for all of us.
Mark Hertsgaard is a Fellow of the New American Foundation and the author of six books, including HOT: Living Through the Next Fifty Years on Earth, just released in paperback.
The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.