Now comes the real challenge: powering a world without fossil fuels.
The Paris climate accord, in its ambition to cut planet-warming carbon emissions, calls for a tectonic shift in energy—in essence, a new global economy to be fueled by zero-carbon sources such as solar and wind.
“In the coming decades the world will have to say goodbye to coal, oil, and gas,” said German Environment Minister Barbara Hendricks. The historic pact seeks to peak emissions in a few decades and then eliminate them.
This shift could happen—not because of the accord itself but because of technological advances and an expanding cadre of influential supporters. Whether it happens quickly enough to avoid the worst impacts of climate change is less clear.
“Even if all the initial targets in Paris are met, we’ll only be part of the way there when it comes to reducing carbon from the atmosphere,” said President Barack Obama. After all, fossil fuels still power almost all vehicles and generate two-thirds of the world's electricity. Obama said that the accord won't solve the climate problem, but it signals “a turning point” by setting up “the architecture" for doing so.
That architecture includes the private sector. “Business leaders came to Paris in unprecedented numbers,” and their commitments give markets a “clear signal” of what the future will look like, said Ban Ki Moon, secretary general of the United Nations. He added: “What was once unthinkable has now become unstoppable.”
Hundreds of businesses and thousands of regions and cities pledged to cut their emissions as part of the Lima-Paris Action Agenda. The companies include Ikea, Coca-Cola, Dell, General Mills, Kellogg’s, Procter & Gamble, Sony, and Walmart.
Their combined pledges exceed India’s annual emissions or those of the global iron and steel sectors, according to a report by Yale’s Data Driven Environmental Solutions. The report said 15 of the world’s largest banks, with nearly $2 trillion in market value, made financial commitments.
Beyond cutting emissions, cities also pledged to divest from fossil fuels. At the climate talks, environmental activists said, Paris and 18 other French municipalities approved steps to divest from companies that produce coal, oil or natural gas. They join at least 60 other cities, including Oslo, Melbourne, and San Francisco, in 10 wealthy countries that support full or partial divestment.
Tech titans stepped up. Microsoft founder Bill Gates announced a billionaires’ club of 28 investors, including Amazon’s Jeff Bezos and Facebook’s Mark Zuckerberg, to help the world shift from fossil fuels. Gates said they aim to get clean-energy ideas out of the lab and into the marketplace. They’ll work with 20 countries, including the United States and China, as part of “Mission Innovation” to double spending on clean energy research and development—to about $20 billion—over the next five years.
This synergy paid off. “Countries have been trying for years to craft an effective climate agreement,” said Bob Perciasepe, president of C2ES, the nonpartisan Center for Climate and Energy Solutions. “What made a difference this time was a groundswell from the front lines—mayors, governors and CEOs who showed they’re taking the lead and pressed government to do more.”
Clean energy alternatives are gaining ground largely because of their cost. Since 2008, prices have plummeted 90 percent for LEDs, 60 percent for large-scale solar, and 40 percent for wind power and batteries, according to a White House statement.
As a result, U.S. wind energy production has tripled and solar has increased more than 20-fold during the last seven years. The Solar Energy Industries Association, a trade group, says 2015 is shaping up to be the strongest ever as it expects a record number of fourth-quarter installations.
Globally, wind and solar are powering ahead as well. The International Energy Agency expects hydropower and other renewables will account for more than 26 percent of power generation in 2020, up from 22 percent in 2013. By 2040, it projects non-hydro renewables will provide half of all power in the European Union and slightly more than a quarter in China, Japan, the U.S., and India.
Renewables are attracting capital. A recent study by Goldman Sachs says the combined market size of low-carbon technologies—including wind, solar, LEDs, hybrid and electric vehicles—now exceeds $600 billion, about the size of the U.S. defense budget.
Their economics could improve even more. “When it comes to the price of solar, even the most optimistic estimates have not been optimistic enough,” writes Sott Nyquist, director of McKinsey & Company's Houston office, which expects solar will be competitive with conventional fuels in most U.S. states by 2020.
In contrast, he says, coal is not likely to get much more efficient, and tighter U.S. regulations are driving up its costs. “For gas, the best technologies in use are already highly efficient,” he adds, “but for renewables, particularly solar, substantive improvements in cost and efficiency are not only possible but likely.”
Indeed, researchers are making solar cells that are smaller, see-through, and sticky so they can be used almost anywhere—whether roads, golf courses, or landfills. In a new white paper, Gates talks about the ability of solar paint to transform any surface into a solar panel.
Also improving: batteries and other means to store solar and wind power for times when the sun doesn’t shine and the wind doesn’t blow. Tesla CEO Elon Musk is building a gigafactory in Las Vegas to mass-produce batteries for not only his electric cars but also solar-powered homes and business.
That’s just the beginning. Scientists are working to create marketable new biofuels, wave and tidal power, fusion energy and smaller, safer nuclear reactors. The Toyota Mirai, a hydrogen fuel-cell car, just debuted in California, and Gates' startup TerraPower aims for initial rollout of its own advanced nuclear reactor in China.
Gates says that while solar and wind power could help meet the 50 percent increase in global energy demand expected by 2050, "we also need to invent new approaches."
Jeffrey D. Sachs, a Columbia University economist, agrees. His Deep Decarbonization Pathways Project, which has enlisted 16 countries to figure out ways to move away from fossil fuels, finds currently available technologies won't likely be good enough to complete this transformation. It says some, such as electric cars and offshore wind turbines, will need to become better and cheaper, and some countries may need more nuclear power.
The world will need to act quickly. Experts say it will likely have to stop all greenhouse gas emissions by mid-century in order to meet the UN accord’s aspirational goal: limit the increase in global temperatures to 1.5 degrees Celsius above pre-industrial levels. The world's temperature has already risen nearly one degree.
Quitting fossil fuels is a herculean task. Despite severe smog that’s choking their cities, China and India plan to build coal-fired power plants so they can cheaply expand access to electricity. Africa, home to half of the world’s people who live without power, is also looking at fossil fuels to meet part of the expected surge in its energy demand.
In the U.S., the world’s second-largest carbon emitter after China, critics in Congress threaten to bar federal funding to implement Obama’s clean energy agenda, and some business leaders remain skeptical. “The Paris climate conference delivered more of the same — lots of promises and lots of issues still left unresolved,” said Stephen D. Eule of the U.S. Chamber of Commerce. Plus, cheap gas has boosted sales of bigger vehicles instead of energy-sipping cars.
Yet many scientists doing cutting-edge research believe technology can overcome seemingly insurmountable challenges.
Harvard chemist Daniel Nocera, who built an "artificial leaf" to produce hydrogen fuel, is one of them. He likes to tell the story of how in the 1890s, New York City was swamped—by horse manure. Then the primary mode of transportation, horses were dropping more than a million pounds a day, creating a sanitation crisis.
The automobile arrived and almost overnight, it replaced horses and cleaned up the streets. Nocera says: “Shift happens.”