Climate change, which is causing sea levels to rise and making extreme weather more likely, represents a major threat. The best way to address climate change is to drastically reduce our greenhouse gas emissions – mainly methane and carbon dioxide. It is difficult to undo damage that has already been done, but by preventing further emissions we may be able to diminish the severity of many of the dangers. Reducing emissions means substituting our most carbon-intensive energy sources, such as coal and natural gas, with cleaner sources, such as hydropower, geothermal, biomass, solar and wind power.

Most developed countries have agreed to significantly reduce their emissions, and many have already made noteworthy progress. Since 2000, over 20 countries, including Denmark, Ukraine, Hungary, Ireland and France, have reduced their greenhouse gas emissions. Of these countries, most have reduced their emissions by more than 10 percent. Denmark, for example, has reduced its CO2 emissions by more than 30 percent and the United States has reduced its by about 8 percent.


United States Efforts

Although the U.S. reduction seems low percentage-wise, it translates to a total annual reduction of about 760 million metric tons since 2005, almost as much as the reduction in the European Union as a whole (770 million metric tons). For comparison, the United States has emitted 6,000 – 7,300 million metric tons of CO2 equivalent each year between 1990 and 2014. Second place in absolute emissions decline in that period goes to the United Kingdom, with a reduction of 170 million metric tons, nearly a quarter of total U.S. reductions.

The United States accounts for only about five percent of global population, but is responsible for 30 percent of global energy use and 28 percent of carbon emissions. This results in a U.S. per capita emissions rate 2.2 times greater than that of China, which houses about 20 percent of the world’s population. Though China has lower per capita emissions, the larger population offsets that, resulting in over 70 percent more carbon dioxide emissions annually than in the United States. Differences in per capita emissions mainly attest to the different levels of development across the globe, though there are significant differences between developed countries as well, reflecting the fact that some nations are more energy-efficient than others. For example, the United States emitted 16.1 tons of carbon per person in 2015, compared to just 6.2 tons/person in the United Kingdom.

When it comes to energy sources, coal is the biggest producer of greenhouse gas emissions in the United States. Between 1885 and 1943, coal was the primary source of energy in the country, and although petroleum and natural gas have since won market share, coal remains one of our three primary energy sources. Only in the early 21st century did natural gas outpace coal and renewables start to take off, decreasing our dependence on coal.

The economic sectors most responsible for greenhouse gas emissions in the United States are electricity generation, industry, and transportation. They account for 29 percent, 21 percent, and 27 percent of total U.S. greenhouse gas emissions, respectively, which is why there is an urgent need for these sectors to transition over to renewable energy sources, such as hydropower, geothermal, wind, solar, and biomass. Currently, renewables account for about 10 percent of total U.S. energy consumption. Electricity generation, industry, and transportation, represent 50 percent, 28 percent, and 14 percent of renewable energy use, respectively, far more than any other sectors.

Although its total renewable energy use seems low, the United States is still the largest consumer of non-hydroelectric renewable energy in the world, accounting for 22 percent of global consumption in 2015. In terms of overall renewable energy use, the United States is second only to China, which has significantly invested in hydropower.

Within the United States, there is a lot of variation between the states on how much progress they have made in reducing their greenhouse gas emissions. Between 2000 and 2015, Washington, DC, and 41 states, including Maine and Ohio, managed to reduce their emissions, but nine states, including Nebraska and Montana, increased their emissions. The emission reductions mostly occurred at the end of the 15-year period, likely due to the impact of the Great Recession and higher gasoline prices, both of which lowered energy consumption. The increasing use of natural gas also played a major role (fracking has made it cheaper than coal, and it emits less carbon dioxide than coal when burned), as did the falling prices of wind and solar installations as well as policies encouraging renewable energy use.


State Successes and the Policies Behind Them

Indeed, state policies play an important role, and help explain why some states are lagging behind while others have substantially reduced their emissions. States participating in the Regional Greenhouse Gas Initiative (RGGI), for example, are obligated to cap CO2 emissions from the power sector at 91 million tons annually, and then achieve a 10 percent reduction in these emissions by 2020. Since the implementation of RGGI, CO2 emissions from the power sector in participating states have decreased by more than 30 percent from baseline levels—though not all of that decrease can be attributed to the RGGI.

In January 2018, California Governor Jerry Brown signed an executive order committing the state to a fleet of five million zero-emission vehicles in use by 2030, upgrading the previous goal of 1.5 million electric vehicles (EVs) on the road by 2025. The order also includes a budget of $2.5 billion to spend on encouraging the purchase of EVs. Furthermore, California has an Advanced Clean Cars Program to reduce pollution from cars. Initiatives like this are a great step in reducing greenhouse gas emissions, as the transportation sector is one of the biggest contributors of greenhouse gas emissions.

California also has an extensive cap-and-trade program, which gives companies allowances, or caps, for how much carbon they can emit each year. Over time, the caps get lowered, forcing companies to either pay to emit more, or find ways to cut their emissions. In addition, the state has a Low Carbon Fuel Standard, requiring petroleum producers to reduce the amount of CO2 in their products. These policies have allowed California to lead the United States in reducing emissions from the transportation sector, which is also the state’s biggest emitter of greenhouse gases.

In 2015, Hawaii became the first U.S. state to pass legislation mandating that all the state’s electricity come from renewable sources before mid-century. This requirement was drafted by Blue Planet Foundation, and attests to the power that non-profits can have in driving change in environmental policy—efforts from local organizations can make a huge difference for the future of renewable energy. The law’s requirement is likely to be fulfilled ahead of time, as Hawaii is already a leader in renewable energy and, in the past five years, has doubled its renewable energy use.

Texas has the highest wind power generation of all 50 states. The state currently has over 10,000 wind turbines generating electricity, and with 80,000 turbines in operation for pumping water, there is vast growth potential for wind power generation. The Texas Renewable Portfolio Standard (RPS), signed by then Governor George Bush in 1999, is one of the reasons behind this great wind capacity. It mandated that utilities create 2,000 new megawatts of renewable energy by 2009. In 2005, the RPS requirement was increased to a total of 5,880 megawatts of renewables by 2015, and 10,000 megawatts by 2025—the latter was achieved 15 years ahead of schedule. Renewable Portfolio Standards have proven successful in facilitating the transition to renewable energy in the 29 states that have adopted them.

Although Texas has the highest absolute wind power generation, states like Iowa, Kansas, and South Dakota, have the largest wind power supply in terms of percentage of total energy use. They obtain 36.6 percent, 29.6 percent, and 30.3 percent of their power from wind, respectively.

Vermont is another great example to follow when it comes to cutting greenhouse gas emissions. In 2005, the state established a law that requires a “50 percent reduction in emissions from the 1990 level of 8.1 million tons by 2028 and a 75 percent reduction by 2050.” In 2015, Vermont committed to an even more ambitious target of limiting its emissions to 80-95 percent below 1990 levels. This translates to a per capita limit of less than two metric tons per year, which is what is deemed necessary to keep global warming below 2° Celsius, as agreed in the Paris Climate Agreement. Annual emissions in Vermont have decreased by about one million tons since 2005, and they continue to decline.

Utilities are a major factor in the increasing use of renewable energy. By switching to renewable energy sources, utilities provide clean power to millions of people. Xcel Energy and MidAmerican Energy, for example, account for 17 percent of U.S. wind power generation. As more utilities follow in MidAmerican Energy’s footsteps and build more renewable energy capacity, emissions across the country will greatly decrease.

Many utility-scale actions are motivated by policies and incentives. For example, financial incentives and programs, such as tax benefits and clean energy fund grants, are used by states to encourage local utilities to switch to cleaner energy. Some states also adopt Feed-in Tariff policies, which guarantee long-term payments to renewable energy developers for the energy they produce. These policies are currently in place in California and Vermont, among others, and have contributed to the emission reductions in these states.

Becoming a country whose energy comes primarily from clean, renewable resources is entirely attainable. Several U.S. states, such as Vermont, Idaho, Washington, Oregon, South Dakota, and Maine, are well on their way to becoming almost completely powered by renewable energy. If we want to save our country and planet from the worst consequences of climate change, those states and countries that have not yet tackled their greenhouse gas emissions must learn from those that have.


Author: Joanne Zulinski