Fifteen years ago, Ken Caldeira, a senior scientist at the Carnegie Institution, calculated that the world would need to add about a nuclear power plant’s worth of clean-energy capacity every day between 2000 and 2050 to avoid catastrophic climate change. Recently, he did a quick calculation to see how we’re doing.
Not well. Instead of the roughly 1,100 megawatts of carbon-free energy per day likely needed to prevent temperatures from rising more than 2 ˚C, as the 2003 Science paper by Caldeira and his colleagues found, we are adding around 151 megawatts. That’s only enough to power roughly 125,000 homes.
At that rate, substantially transforming the energy system would take, not the next three decades, but nearly the next four centuries. In the meantime, temperatures would soar, melting ice caps, sinking cities, and unleashing devastating heat waves around the globe (see “The year climate change began to spin out of control”).
Caldeira stresses that other factors are likely to significantly shorten that time frame (in particular, electrifying heat production, which accounts for a more than half of global energy consumption, will significantly alter demand). But he says it’s clear we’re overhauling the energy system about an order of magnitude too slowly, underscoring a point that few truly appreciate: It’s not that we aren’t building clean energy fast enough to address the challenge of climate change. It’s that—even after decades of warnings, policy debates, and clean-energy campaigns—the world has barely even begun to confront the problem.
The UN’s climate change body asserts that the world needs to cut as much as 70 percent of greenhouse-gas emissions by midcentury to have any chance of avoiding 2 ˚C of warming. But carbon pollution has continued to rise, ticking up 2 percent last year.
So what’s the holdup?
Beyond the vexing combination of economic, political, and technical challenges is the basic problem of overwhelming scale. There is a massive amount that needs to be built, which will suck up an immense quantity of manpower, money, and materials.
For starters, global energy consumption is likely to soar by around 30 percent in the next few decades as developing economies expand. (China alone needs to add the equivalent of the entire US power sector by 2040, according to the International Energy Agency.) To cut emissions fast enough and keep up with growth, the world will need to develop 10 to 30 terawatts of clean-energy capacity by 2050. On the high end that would mean constructing the equivalent of around 30,000 nuclear power plants—or producing and installing 120 billion 250-watt solar panels.
|What we should be doing*||What we're actually doing†|
|Megawatts per day||1,100||151|
|Megawatts per year||401,500||55,115|
|Megawatts in fifty years||20,075,000||2,755,750|
|Years to add 20 Terrawatts||50||363|
|Sources: Carnegie Institution, Science, BP||*If we had started at this rate in 2000||†Actual average rate of carbon-free added per day from 2006-2015|
There’s simply little financial incentive for the energy industry to build at that scale and speed while it has tens of trillions of dollars of sunk costs in the existing system.
“If you pay a billion dollars for a gigawatt of coal, you’re not going to be happy if you have to retire it in 10 years,” says Steven Davis, an associate professor in the Department of Earth System Science at the University of California, Irvine.
It’s somewhere between difficult and impossible to see how any of that will change until there are strong enough government policies or big enough technology breakthroughs to override the economics.
In late February, I sat in Daniel Schrag’s office at the Harvard University Center for the Environment. His big yellow Chinook, Mickey, lay down next to my feet.
Schrag was one of President Barack Obama’s top climate advisors. As a geologist who has closely studied climate variability and warming periods in the ancient past, he has a special appreciation for how dramatically things can change.
Sitting next to me with his laptop, he opened a report he had recently coauthored assessing the risks of climate change. It highlights the many technical strides that will be required to overhaul the energy system, including better carbon capture, biofuels, and storage.
The study also notes that the United States adds roughly 10 gigawatts of new energy generation capacity per year. That includes all types, natural gas as well as solar and wind. But even at that rate, it would take more than 100 years to rebuild the existing electricity grid, to say nothing of the far larger one required in the decades to come.
“Is it possible to accelerate by a factor of 20?” he asks. “Yeah, but I don’t think people understand what that is, in terms of steel and glass and cement.”
Climate observers and commentators have used various historical parallels to illustrate the scale of the task, including the Manhattan Project and the moon mission. But for Schrag, the analogy that really speaks to the dimensions and urgency of the problem is World War II, when the United States nationalized parts of the steel, coal, and railroad industries. The government forced automakers to halt car production in order to churn out airplanes, tanks, and jeeps.
The good news here is that if you direct an entire economy at a task, big things can happen fast. But how do you inspire a war mentality in peacetime, when the enemy is invisible and moving in slow motion?
“It’s a quantum leap from where we are today,” Schrag says.
The fact that the really devastating consequences of climate change won’t come for decades complicates the issue in important ways. Even for people who care about the problem in the abstract, it doesn’t rate high among their immediate concerns. As a consequence, they aren’t inclined to pay much, or change their lifestyle, to actually address it. In recent years, Americans were willing to increase their electricity bill by a median amount of only $5 a month even if that “solved,” not eased, global warming, down from $10 15 years earlier, according to a series of surveys by MIT and Harvard.
It’s conceivable that climate change will someday alter that mind-set as the mounting toll of wildfires, hurricanes, droughts, extinctions, and sea-level rise finally forces the world to grapple with the problem.
But that will be too late. Carbon dioxide works on a time delay. It takes about 10 years to achieve its full warming effect, and it stays in the atmosphere for thousands of years. After we’ve tipped into the danger zone, eliminating carbon dioxide emissions doesn’t decrease the effects; it can only prevent them from getting worse. Whatever level of climate change we allow to unfold is locked in for millennia, unless we develop technologies to remove greenhouse gases from the atmosphere on a massive scale (or try our luck with geoengineering).
This also means there’s likely to be a huge trade-off between what we would have to pay to fix the energy system and what it would cost to deal with the resulting disasters if we don't. Various estimates find that cutting emissions will shrink the global economy by a few percentage points a year, but unmitigated warming could slash worldwide GDP more than 20 percent by the end of the century, if not far more.
Arguably the most crucial step to accelerate energy development is enacting strong government policies. Many economists believe the most powerful tool would be a price on carbon, imposed through either a direct tax or a cap-and-trade program. As the price of producing energy from fossil fuels grows, this would create bigger incentives to replace those plants with clean energy (see “Surge of carbon pricing proposals coming in the new year”).
“If we’re going to make any progress on greenhouse gases, we’ll have to either pay the implicit or explicit costs of carbon,” says Severin Borenstein, an energy economist at the University of California, Berkeley.
But it has to be a big price, far higher than the $15 per ton it cost to acquire allowances in California’s cap-and-trade program late last year. Borenstein says a carbon fee approaching $40 a ton “just blows coal out of the market entirely and starts to put wind and solar very much into the money,” at least when you average costs across the lifetime of the plants.
Others think the price should be higher still. But it’s very hard to see how any tax even approaching that figure could pass in the United States, or many other nations, anytime soon.
The other major policy option would be caps that force utilities and companies to keep greenhouse emissions below a certain level, ideally one that decreases over time. This regulations-based approach is not considered as economically efficient as a carbon price, but it has the benefit of being much more politically palatable. American voters hate taxes but are perfectly comfortable with air pollution rules, says Stephen Ansolabehere, a professor of government at Harvard University.
Fundamental technical limitations will also increase the cost and complexity of shifting to clean energy. Our fastest-growing carbon-free sources, solar and wind farms, don’t supply power when the sun isn’t shining or the wind isn’t blowing. So as they provide a larger portion of the grid’s electricity, we’ll also need long-range transmission lines that can balance out peaks and valleys across states, or massive amounts of very expensive energy storage, or both (see “Relying on renewables alone significantly inflates the cost of overhauling energy”).
The upshot is that we’re eventually going to need to either supplement wind and solar with many more nuclear reactors, fossil-fuel plants with carbon capture and other low-emissions sources, or pay far more to build out a much larger system of transmission, storage and renewable generation, says Jesse Jenkins, a researcher with the MIT Energy Initiative. In all cases, we’re still likely to need significant technical advances that drive down costs.
All of this, by the way, only addresses the challenge of overhauling the electricity sector, which currently represents less than 20 percent of total energy consumption. It will provide a far greater portion as we electrify things like vehicles and heating, which means we’ll eventually need to develop an electrical system several times larger than today’s.
But that still leaves the “really difficult parts of the global energy system” to deal with, says Davis of UC Irvine. That includes aviation, long-distance hauling, and the cement and steel industries, which produce carbon dioxide in the manufacturing process itself. To clean up these huge sectors of the economy, we’re going to need better carbon capture and storage tools, as well as cheaper biofuels or energy storage, he says.
These kinds of big technical achievements tend to require significant and sustained government support. But much like carbon taxes or emissions caps, a huge increase in federal research and development funding is highly unlikely in the current political climate.
So should we just give up?
There is no magic bullet or obvious path here. All we can do is pull hard on the levers that seem to work best.
Environmental and clean-energy interest groups need to make climate change a higher priority, tying it to practical issues that citizens and politicians do care about, like clean air, security, and jobs. Investors or philanthropists need to be willing to make longer-term bets on early-stage energy technologies. Scientists and technologists need to focus their efforts on the most badly needed tools. And lawmakers need to push through policy changes to provide incentives, or mandates, for energy companies to change.
The hard reality, however, is that the world very likely won’t be able to accomplish what’s called for by midcentury. Schrag says that keeping temperature increases below 2 ˚C is already “a pipe dream,” adding that we’ll be lucky to prevent 4 ˚C of warming this century.
That means we’re likely to pay a very steep toll in lost lives, suffering, and environmental devastation (see “Hot and violent”).
But the imperative doesn’t end if warming tips past 2 ˚C. It only makes it more urgent to do everything we can to contain the looming threats, limit the damage, and shift to a sustainable system as fast as possible.
“If you miss 2050,” Schrag says, “you still have 2060, 2070, and 2080.”