In May 2008, Sen. John McCain traveled to Portland, Oregon, and delivered a speech that no Republican presidential candidate would consider giving today.

It doesn't matter "whether we call it 'climate change' or 'global warming,'" McCain warned. "Among environmental dangers it is surely the most serious of all." McCain went on to propose a cap-and-trade plan far more aggressive than the power-plant rules the Obama administration is announcing today.

It was perfectly acceptable to be a national Republican who worried about climate change

McCain's plan would have limited emissions not just from power plants, but also from transportation, manufacturing, and commercial businesses. It sought to bring total US emissions 66 percent below 2005 levels by 2050. It wasn't quite as ambitious as the cap-and-trade plan Obama proposed (here's a good comparison, if you're interested), but it was a real effort to deal with an urgent problem.

Three months later, Sarah Palin accepted McCain's invitation to join the ticket — which meant running on is cap-and-trade plan. Then, at the September convention, the Republican Party officially endorsed the McCain/Palin ticket, which still included a cap-and-trade plan. When Gwen Ifill asked Sarah Palin whether she supported capping carbon emissions, Palin's answer left no room for confusion: "I do," she replied.

This wasn't a huge surprise. Not every national Republican was worried about climate change in those days. But in the mid-Aughts, it was perfectly acceptable to be a national Republican who worried about climate change. You could even sit on a couch with Nancy Pelosi and fret about global warming on TV:





President George W. Bush was worried about climate change, too. As Peter Baker records in his book Days of Fire:

[Bush] found the science increasingly persuasive and believed more needed to be done. The end of his presidency loomed, and he did not want to be known as the president who stood by while a crisis gathered. Now he bristled not at the Hollywood types but at the notion that he did not care. In the past eighteen months, he had cited the danger of climate change in his State of the Union address for the first time, convened a conference of major world polluters to start working on an international accord to follow Kyoto, and signed legislation cutting gasoline consumption and, by extension, greenhouse gases. He even invited his old rival Al Gore for a forty-minute talk about global warming.

In 2008, it still looked plausible that with American leadership, the world could limit the rise in temperatures to about two degrees Celsius. Today, that goal looks laughable. We're on track to see temperatures rise by about four degrees Celsius. It's worth quoting my colleague Brad Plumer at length on what that might mean:

Four degrees (or 7.2° Fahrenheit) may not sound like much. But the world was only about 4°C to 7°C cooler, on average, during the last ice age, when large parts of Europe and the United States were covered by glaciers. The IPCC concluded that changing the world's temperature in the opposite direction could bring similarly drastic changes, such as "substantial species extinctions," or irreversibly destabilizing Greenland's massive ice sheet. In 2013, researchers with the World Bank took a look at the science on projected effects of 4°C warming and were appalled by what they found...Most climate models currently make predictions in a linear fashion. That is, they basically assume that the impacts of 4°C of warming will be twice as bad as those of 2°C. But that might be wrong. Impacts may interact with each other in unpredictable ways. Current agriculture models, they noted, don't have a good sense for what will happen to crops if heat waves, droughts, new pests and diseases all combine together. Here's an analogy that Hans Joachim Schellnhuber, who helped compile some of the research for the World Bank, likes to use. "Take the human body. If your temperature rises 2°C, you have a significant fever. If it rises 4°C or 6°C you can die. It's not a linear change. You're pushing a complex system outside the range it's adapted to. And all our assessments indicate that once you do that, the system's resilience gets stretched thin." Perhaps most significantly, the World Bank report wasn't even sure if humanity could adapt to a 4°C world. At the moment, the large lender is helping poorer countries prepare for global warming by building seawalls, conducting crop research, and improving freshwater management. But, as an internal review found, most of these efforts are being done with relatively small temperature increases in mind. The bank wasn't planning for 3°C or 4°C of global warming - because no one really knew what that might entail. "[G]iven that uncertainty remains about the full nature and scale of impacts," the report said, "there is also no certainty that adaptation to a 4°C world is possible." And its conclusion was stark: "The projected 4°C warming simply must not be allowed to occur."

The power plant regulations the Obama administration will announce today are far less ambitious than the proposal McCain offered in Oregon in 2008. They're less ambitious than the proposals Newt Gingrich championed through the Aughts. They're far less than what's required to keep the rise in temperatures to two degrees Celsius.

"there is also no certainty that adaptation to a 4°C world is possible"

But they're probably at the outer limit of what can be done so long as the Republican Party refuses to even believe in climate change, much less work with the Obama administration on a bill. The good news, if there is any, is that the Republican Party hasn't always refused to believe in climate change. There was even a time when its key national leaders were committed to doing something about it. Those leaders are still around today. They could still do something about it today.

"We have many advantages in the fight against global warming, but time is not one of them," McCain said in 2008. "Instead of idly debating the precise extent of global warming, or the precise timeline of global warming, we need to deal with the central facts of rising temperatures, rising waters, and all the endless troubles that global warming will bring. We stand warned by serious and credible scientists across the world that time is short and the dangers are great. The most relevant question now is whether our own government is equal to the challenge."

We're about to find out.