Speaking at the United Nations in December, House Speaker Nancy Pelosi drew cheers by saying the United States was "still in" the Paris Climate Agreement. Green activists applauded Pelosi's defense of the international climate accord, which President Trump had vowed to exit. These activists claim that remaining in the Paris Agreement will help reduce global emissions.

They are wrong.

European leaders have spent years trying and pointedly failing to solve the climate crisis with regulation. Whether intentionally or not, U.S. policymakers have mostly avoided top-down solutions. And counterintuitively, or perhaps it should have been intuitive, the U.S. now leads the developed world in reducing carbon emissions.

Policymakers can learn an important lesson from this. The key to fighting climate change is to unleash the power of the free market, not to embrace every green politician's or activist's nutty new idea.

European countries have not had much success using regulation to fight climate change. Germany recently spent 150 billion euros on an aggressive campaign to lower emissions by mandating across-the-board fossil fuel reductions. As part of this quest for renewable energy, Germany foreswore cleaner-burning fossil fuels such as natural gas. But because solar and wind don't generate enough consistent power, this means that Germany must rely on coal, the dirtiest fossil fuel, to generate 40% of its electricity. As a result, Germany is projected to fall short of nearly every national and European Union clean energy standard this year.

Germany's experience is typical for bureaucratic climate policies, and it stands in sharp contrast to the American experience. The U.S., though heavily criticized for not signing the 1997 Kyoto Protocol, is curbing emissions today much faster than any country that actually did sign the agreement.

That's because, instead of banning fossil fuels outright, the U.S. embraced natural gas amid a boom in its production. Thanks to a process called hydraulic fracturing or "fracking," we've managed to tap new reserves of natural gas. In 2015, the U.S. surpassed Saudi Arabia and Russia to become the world's top producer of natural gas. By 2018, energy companies produced over 60% more natural gas than they had two decades earlier. This newfound abundance of natural gas has helped our nation transition away from coal, which emits twice as much carbon dioxide.

Thanks to this shift, U.S. carbon dioxide emissions have hit 30-year lows, even as global emissions have increased by 50% during the same period. And since 2005, natural gas has done more to reduce power sector dioxide emissions than all renewable energy sources combined, according to the Energy Information Administration.

By eschewing regulation, America has also spurred additional emissions-reducing innovations in the private sector. Freed from red tape, U.S. energy firms have been able to devise and implement a host of groundbreaking green technologies. For example, a new technology called CleanWave strips chemicals from fracking wastewater using positively charged ions and bubbles. The Texas-based energy firm Apache reduces greenhouse gas emissions by powering fracking engines with natural gas instead of diesel.

Energy firms have also joined together to reduce emissions. Recently, 65 natural gas and oil companies formed the Environmental Partnership in order to better fight climate change. Over the past year, the coalition conducted more than 156,000 methane leak surveys across 78,000 sites and repaired 99% of detected leaks in 60 days or less.

The Environmental Partnership has also replaced and retrofitted methane-emitting valves used in natural gas production. Replacing such valves can cut emissions by up to 60%, according to the Environmental Protection Agency.

While the rest of the world fumbles with green energy policies, the U.S. continues to reduce emissions. We don't need regulation to guarantee future success. American firms will continue to combat climate change, as long as we let them.

Drew Johnson is a senior fellow at the National Center for Public Policy Research.