Ahead of Earth Day, an Energy In Depth review of the latest government data shows that U.S. emissions of carbon dioxide and three air pollutants responsible for millions of deaths worldwide have significantly declined since the shale revolution began. This is a trend that multiple reputable third parties agree can be traced directly to increased natural gas use made possible by hydraulic fracturing, further underscoring the folly of the “Keep It In the Ground” movement’s “ban fracking” agenda.

U.S. Energy Information Administration (EIA) data show that natural gas consumption increased 25 percent from 2005 to 2016. During that same timespan, the most recent EPA Greenhouse Gas Inventory shows U.S. carbon dioxide emissions have declined 13 percent, while overall greenhouse gas emissions are at their lowest levels since 1992. The latest EPA data also show that sulfur dioxide, nitrogen oxide and fine particulate matter emissions are down 82, 49 and 32 percent, respectively, since 2005.

Natural gas emits far less carbon dioxide (CO2) and nitrogen oxide (NOx) than other traditional fuels when burned, and emits virtually no sulfur dioxide (SO2) and fine particulate matter (PM2.5). These facts led the International Energy Agency (IEA) to recently state that, “The emissions from natural gas combustion are well-known and show clear advantages for gas relative to other fossil fuels.” IEA also stated in its recent World Energy Outlook:

“The role that natural gas can play in the future of global energy is inextricably linked to its ability to help address environmental problems. With concerns about air quality and climate change looming large, natural gas offers many potential benefits if it displaces more polluting fuels.”

As the following EID infographic shows, increased use of natural gas — made possible by advances in horizontal drilling and hydraulic fracturing technologies —has allowed the United States to lead all major industrialized countries in carbon reductions this century, while growing its economy significantly, a previously unheard of decoupling trend.

The U.S. Energy Information Administration (EIA) and IEA have both credited natural gas for a vast majority of the carbon reductions highlighted above.

EIA recently stated:

“The underlying energy consumption trends that resulted in these changes — mainly because more electricity has been generated from natural gas than from other fossil fuels — have helped to lower the U.S. emissions level since 2005.”

IEA stated in 2017 that:

“The US power sector has led the world in cutting CO2 emissions since 2008, thanks largely to natural gas… Emissions in the United States last year were at their lowest levels since 1992, a period during which the economy grew by 80%.”

A recent EIA graphic shows how the U.S. CO2 savings attributable to increased natural gas use is about 72 percent greater than has been saved the savings by using non-carbon energy sources, like renewables.

This can be traced to the fact that natural gas-fired electricity generation has increased 81 percent since 2005, dropping power sector carbon emissions to their lowest levels since 1988. This is the primary reason the United States has achieved these emissions reductions without ratifying the Kyoto Protocol or adopting cap-and-trade legislation. In fact, the U.S. has already achieved the 2025 emission reduction targets laid out in the now-repealed Clean Power Plan. And despite the Trump administration’s stated intent of withdrawing from the Paris climate agreement, United Nations Energy Programme Chief Erik Solheim recently said:

“In all likelihood, the United States will live up to its Paris commitment, not because of the White House, but because of the private sector.”

A 2016 report by researchers from the Breakthrough Institute, who Time Magazine has called “heroes of the environment,” agrees with Solheim that the U.S. can meet its Paris commitments without regulatory intervention by continuing to facilitate market-driven policies that allow natural gas to thrive.

But what about methane emissions that the “Keep It In the Ground” movement claims are on the rise, wiping out natural gas’ climate benefits? The latest EPA GHGI shows that natural gas system methane emissions have declined 3.5 percent since 2005, while overall U.S. methane emissions have decreased 4.5 percent. Furthermore, recent EPA and Global Carbon Project data show that U.S. oil and natural gas system methane emissions account for just 1.4 percent of overall global methane emissions. A recent Gas Technology Institute’s Center for Methane Research report also finds that U.S. natural gas system methane emissions account for just 0.20 percent of global climate forcing.

Put another way, natural gas emissions from U.S. natural gas development are having a minimal impact on global warming and coming nowhere close to negating natural gas’ climate benefits. That is why even the Intergovernmental Panel on Climate Change (IPCC) — widely regarded as the definitive voice on global warming — notes in its Fifth Assessment Report:

“[T]he rapid deployment of hydraulic fracturing and horizontal-drilling technologies, which has increased and diversified the gas supply…is an important reason for a reduction of GHG emissions in the United States.”

As significant as natural gas’ contributions to greenhouse gas reductions has been since 2005, its’ role in reducing U.S. air pollution has arguably been even greater.

A recent IEA report notes that poor air quality kills approximately 6.5 million people a year, making it the fourth highest cause of death in the world. The IEA also recently noted that increased natural gas use helps reduce the three most dangerous pollutants contributing to these staggering figures — SO2, NOx and PM2.5:

“The edge of natural gas over other combustible fuels is reinforced when considering emissions of the main air pollutants, including fine particulate matter (PM2.5), sulfur oxides, mainly sulfur dioxide (SO2), and nitrogen oxides (NOX). These three pollutants are responsible for the most widespread impacts of air pollution…”

University of California-Berkeley Professor of Physics Richard Muller has added some mathematical perspective to the latter fact, stating:

“Shale gas results in a 400-fold reduction of PM2.5, a 4,000-fold reduction in sulfur dioxide (SO2), a 70-fold reduction in nitrous oxides (NOx) and more than a 30-fold reduction in mercury.”

The EPA has previously noted that SO2 is “of greatest concern” with regard to health, due in large part to the fact that it combines with other pollutants to form PM2.5. EPA also notes on its website that:

“Short-term exposures to SO2 are linked with respiratory effects including difficulty breathing and increased asthma symptoms. These effects are particularly problematic for asthmatics while breathing deeply such as when exercising or playing. Short-term exposures to SO2 have also been connected to increased emergency department visits and hospital admissions for respiratory illnesses, particularly for at-risk populations including children, older adults and those with asthma. SO2 contributes to particle formation with associated health effects.”

EIA notes that natural gas “produces virtually no SO2 emissions and negligible levels of PM2.5,” which is reflected in the fact that U.S. SO2 emissions have declined 82 percent since 2005 at the same time natural gas consumption has increased 25 percent and natural gas-fired electricity generation has increased 81 percent.

U.S. PM2.5 emissions have declined 32 percent since 2005, while atmospheric concentrations have decreased approximately 40 percent.

Similar to the SO2 emission reductions discussed earlier, the significance of these reductions really can’t be overstated and can be largely credited to natural gas.

EPA’s website notes that PM2.5 is a byproduct of chemical reactions between a number of pollutants, most notably nitrogen oxides and sulfur dioxides, and present a myriad of health and environmental challenges:

“Exposures to PM, particularly fine particles referred to as PM2.5, can cause harmful effects on the cardiovascular system including heart attacks and strokes. These effects can result in emergency department visits, hospitalizations and, in some cases, premature death. PM exposures are also linked to harmful respiratory effects, including asthma attacks.”

“Fine particles (PM2.5) are the main cause of reduced visibility (haze) in parts of the U.S., including many national parks and wilderness areas. PM can also be carried over long distances by wind and settle on soils or surface waters. The effects of settling include: making lakes and streams acidic; changing the nutrient balance in coastal waters and large river basins; depleting the nutrients in soil; damaging sensitive forests and farm crops; and affecting the diversity of ecosystems. PM can stain and damage stone and other materials, including culturally important objects such as statues and monuments.”

Muller has been more blunt and to the point in discussing PM2.5 — and natural gas’ role in reducing it — saying:

“For shale gas is a wonderful gift that has arrived just in time. It can not only reduce greenhouse gas emissions, but also reduce a deadly pollution known as PM2.5 that is currently killing over three million people each year, primarily in the developing world.

The sobering reality of Muller’s latter statement is illustrated in the following interactive map from the State of Global Air/2018 report that was released this week, showing PM2.5 levels are at extremely dangerous levels in much of the world, especially compared to North America, where use of clean-burning natural gas has significantly reduced the pollutant, literally saving lives.


In addition to emitting virtually no SO2 or PM2.5, natural gas also emits less than a quarter of the nitrogen oxide of coal, which has contributed to NOx emissions declining 49 percent since 2005, according to the most recent EPA data.

NOx is most widely known as a major precursor to ground level ozone formation. As EPA states:

“Oxides of nitrogen react with volatile organic compounds to form ozone and react with ammonia and other compounds to form particle pollution resulting in associated public health and environmental effects. Deposition of nitrogen oxides contributes to the acidification and nutrient enrichment (eutrophication, nitrogen saturation) of soils and surface waters. These effects can change the diversity of ecosystems.”

Anti-fracking activists have repeatedly claimed that oil and natural gas development has led to increases in ozone. But this data confirms an inconvenient reality for the “Keep It In the Ground” movement: the shale gas boom has significantly reduced NOx emissions and, subsequently, ozone levels, which have declined 22 percent since 2005.

Unable to refute this overwhelming evidence of natural gas’ contributions to improved air quality on a large scale in the U.S., many “Keep It In the Ground” activists continue to insist that local emissions from oil and natural gas production sites trump these air quality improvements.

But that argument has been debunked as well, as no fewer than 17 studies based on actual oil and natural gas site measurements show emissions are protective of human health. The most comprehensive of these studies, a 2017 Colorado Department of Health and Environment health assessment based on 10,000 air samples from parts of the state with “substantial” oil and gas operations, concluded:

“[T]he risk of harmful health effects is low for residents living [near] oil and gas operations,” and that “results from exposure and health effect studies do not indicate the need for immediate public health action.”

Natural Gas Has Facilitated — Not Impeded — Renewable Growth

To be clear, renewables and other non-carbon energy sources have contributed to these emission declines as well. However, it is important to note that natural gas is also an important part of the renewable discussion, as it provides necessary backup for intermittent energy sources such as wind and solar.

A 2016 National Bureau of Economic Research report found fracking has actually helped renewable energy growth — finding that a one percent increase in the electrical generation share of “fast reacting fossil technologies” (translation: natural gas) is associated with a 0.88 percent increase in renewable generation capacity in the long term.” In other words, renewable electricity generation has grown at roughly the same rate as natural gas-fired electrical generation over the past two-plus decades, according to the report:

“Our paper calls attention to the fact that renewables and fast-reacting fossil technologies appear as highly complementary and that they should be jointly installed to meet the goals of cutting emissions and ensuring a stable supply.”

Echoing this report, the IEA recently stated, “The flexibility that natural gas brings to an energy system can also make it a good fit for the rise of variable renewables such as wind and solar PV.”


The latest government data illustrates the fact that increased natural gas use since 2005 has directly led to significant reductions of greenhouse gas emissions and three dangerous air pollutants responsible for millions of deaths throughout the world.

These are environmental achievements worth celebrating on Earth Day.

But ironically, “The Keep It In the Ground” movement that is comprised of some of the same organizations that helped launch the first Earth Day 48 years ago maintains that despite the undeniable evidence of natural gas use driving down emissions, a ban on fracking and all oil and gas development is necessary. In fact, its one of their primary objectives, and as such it seems fair to question who the science deniers really are.