Eduardo Porter of the NY Times discusses a new UN report on climate change detailing the actual steps needed to stay within the 2 degree Centigrade temperature elevation to which world leaders paid lip service a few years ago. He doesn't say it but I will - it may be doable, but we aren't going to do it.

From the Times:

Here’s what your future will look like if we are to have a shot at preventing devastating climate change.

Within about 15 years every new car sold in the United States will be electric. In fact, by midcentury more than half of the American economy will run on electricity. Up to 60 percent of power might come from nuclear sources. And coal’s footprint will shrink drastically, perhaps even disappear from the power supply.

This course, created by a team of energy experts, was unveiled on Tuesday in a report for the United Nations that explores the technological paths available for the world’s 15 main economies to both maintain reasonable rates of growth and cut their carbon emissions enough by 2050 to prevent climatic havoc.

Within fifteen years the US will have that much installed nuclear capacity? Odd, since the political will to build new facilities seems to be nil. This is from the World Nuclear Association:

In the USA there are plans for 13 new reactors, and two combined construction and operating licences for these were issued early in 2012 while five more are under review. All are for late third-generation plants, and a further proposal is for two ABWR units. it is expected that some of the new reactors will be on line by 2020.

A whole lucky 13 new plants? That hardly expands our base. From Wikipedia:

Nuclear power in the United States is provided by 100 commercial reactors (65 pressurized water reactors and 35 boiling water reactors) licensed to operate at 65 nuclear power plants, producing a total of 790 TWh of electricity, which was 19.2% of the nation's total electric energy generation in 2011.[1] The United States is the world's largest supplier of commercial nuclear power.

The notion that the numbers won't add up is hardly news. This is from Roger Pielke's blog late this spring:

I did a lot this math in The Climate Fix and in various peer reviewed papers, but you don't need to believe me. Here is Caldeira et al. in Science in 2003:

To achieve stabilization at a 2°C warming, we would need to install ~900 ± 500 MW [mega-watts] of carbon emissions-free power generating capacity each day over the next 50 years. This is roughly the equivalent of a large carbon emissions-free power plant becoming functional somewhere in the world every day. In many scenarios, this pace accelerates after mid-century. . . even stabilization at a 4°C warming would require installation of 410 MW of carbon emissions-free energy capacity each day.

Get that? A nuclear power plant-worth of carbon-free energy per day, every day until 2050.

I have not attempted to compare the latest UN figures with the 2003 paper mentioned above, but still. The 60% figure cited by Mr. Porter is from what the UN calls the "High Nuclear" scenario. In their base case, nuclear electricity rises from 21% to 30% of all electricity, but electricity uses also greatly expands (replacing petro-based transportation as well as residential heating and cooking). From the UN report:

To meet demand, net electricity generation grows by nearly 75% relative to 2010, as shown in the middle right panel of Figure 6. At the same time, a gradual shift in the mix of generation sources results in nearly complete decarbonization of electricity by 2050, with a CO2 intensity of 18 gCO2 per kWh (5 gCO2 per GJ), a 95% reduction from its 2010 value. The 2050 generation mix is a blend of 40% renewables (hydro, solar, wind, biomass, and geothermal), 30% nuclear, and 30% fossil fuel (coal, natural gas) with CCS (CCS = carbon sequestration).

If nuclear rises from 20% to 30% of electric output and electric output rises from 100 to 175 units, then nuclear capacity increases from 20 units to 52.5 units. If we are going to more than double our nuclear capacity in the next thirty-five years, 13 new plants to supplement the 100 online will hardly be a credible start.

Mr. Porter is droll here:

[The report] offers a sobering conclusion. We might be able to pull it off. But it will take an overhaul of the way we use energy, and a huge investment in the development and deployment of new energy technologies. Significantly, it calls for an entirely different approach to international diplomacy on the issue of how to combat climate change.

“This will require a heroic cooperative effort,” said Jeffrey D. Sachs, the Columbia University economist who directs the Sustainable Development Solutions Network at the United Nations, which convened the multinational teams.

Yes, international cooperation is sky-high just now.

The teams, one in each of the 15 countries, looked at what would be necessary to keep the atmosphere from warming more than 2 degrees Celsius, 3.6 degrees Fahrenheit, above the preindustrial average of the late 19th century, a target that most of the world committed to at the climate summit meeting in Copenhagen five years ago. To do so, CO 2 emissions from industry and energy use would have to fall to at most 1.6 tons a year for every person on the planet by midcentury.

That is less than a tenth of annual American emissions per person today and less than a third of the world average. And we haven’t quite figured out how to get from here to there.

But don't stop believing!

Most important, the assessment offers an opportunity to end decades of inconsequential horse-trading over climate change and to start addressing the problem for real.

Five years since political leaders from countries around the world committed to do whatever it took to keep global temperatures from rising more than two degrees above the preindustrial average, no one had taken the trouble, until now, to evaluate how that might be achieved.

Lacking any understanding of the feasibility of the exercise, governments postured and jockeyed over which country should be responsible for what, offering as little as they could get away with in actual reductions in greenhouse gas emissions, whether the collective effort met the two-degree commitment or not.

“If governments don’t have any idea of what two degrees means in their countries, how can they commit to two degrees?” asked Guido Schmidt-Traub, executive director of the Sustainable Development Network.

Oh, stop - the governments knew what their 2 degree commitment meant - increased donations and decreased gnawing on left-wing politicians from energetic Greens. The reality-based community has never been particularly interested in the realities of achieving their aspirations.

And the obvious political problem with delivering a specific roadmap is that the unreality of the exercise will quickly set in. So is it time to bring on the geoengineers? Oh, sure, because confidence in Big Government is also sky-high.

Not to be all negative, of course.