What does the spike in U.S. greenhouse gas emissions mean?

By Robert C. Jones Jr.

What does the spike in U.S. greenhouse gas emissions mean?

By Robert C. Jones Jr.
University of Miami experts weigh in on the largest increase in carbon emissions in eight years.

A 3.4 percent rise in anything may sound miniscule, but try telling that to the legion of concerned scientists who have been sounding the alarm about climate change for the past decade and this week learned that U.S. greenhouse gas emissions rose by that very figure in 2018—the biggest increase in eight years. 

The smallest spike in carbon emissions, they said, is cause for alarm. This increase, they explain, only hastens our planet’s journey toward an environmental nightmare of soaring temperatures, melting ice sheets, rising sea levels, more extreme heat waves, and an uptick in super storms. 

Published Tuesday by the independent economic research firm Rhodium Group, the report on the increase in U.S. carbon emissions is preliminary. But the 3.4 percent figure, based on data from the U.S. Energy Information Administration and other sources, is added fuel for scientists who agree that the world must adopt stronger emissions standards to prevent a climate disaster. 

Carbon emissions increased in all four sectors as identified by Rhodium: buildings, industry, transportation, and electric power. And what is alarming is that the spike occurred even as U.S. coal-fired power plants closed at near-record levels last year, despite the Environmental Protection Agency rolling back Obama-era policies that imposed strict emissions limits and pollution standards. 

“In the scientific community the urgency has always been clear—if we want to substantially slow the warming of the climate, then dramatic reductions in CO2 are required,” said Ben Kirtman, a professor of atmospheric science at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science. 

But it is not solely a U.S. crisis, as greenhouse gas emissions have accelerated at an incredible rate around the world. China, for example, now produces 27 percent of the world’s carbon emissions—more than the U.S. and European Union combined. 

And if that number isn’t enough to cause panic, just consider that a recent report by the U.N. Intergovernmental Panel on Climate Change (IPCC) warns that the world has just over a decade to cut carbon emissions by 50 percent to avoid a 1.5 degrees Celsius (2.7 degrees Fahrenheit) warming above preindustrial levels. “We are already 1 degree Celsius warmer than preindustrial levels,” said Kirtman. “This is why this recent uptick in U.S. CO2 emissions is disconcerting.” 


View the University of Miami Climate Change Special Report.


Simply stabilizing greenhouse gas emissions at the current rate won’t be enough to stop the warming trend. It will take “dramatic and immediate reductions in CO2 emissions, both for the U.S. and globally, to achieve that goal,” said Brian Soden, a professor of atmospheric sciences at the Rosenstiel School who specializes in the use of satellite observations to test and improve computer simulations of Earth’s climate. 

“In order to stabilize the climate and prevent additional warming, net emissions have to go to zero,” said Soden. “The climate has already warmed by about 1 degree Celsius due to human emissions of greenhouse gases. However, the full warming from our past emissions has not yet been realized due to the large thermal inertia of the oceans. So some additional warming is inevitable.” 

To limit that additional warming, according to Soden, global emissions of greenhouse gases must peak before the year 2020, decline to zero within the next 50 years, and then become negative thereafter. “Negative emissions means there is a withdrawal of CO2 from the atmosphere through afforestation and carbon capture with sequestration in underground reservoirs,” he said. 

Reversing the increase in emissions will also require implementing policies that require greater use of energy sources that are low in carbon emissions. But while the development of alternative energy sources has significantly increased, “the free-market forcing just isn’t fast enough. Large scale policy must be implemented,” said Kirtman, who is also director of NOAA’s Cooperative Institute for Marine and Atmospheric Studies based at the Rosenstiel School. 

Implementing such policies could be difficult to achieve. Nearly two years ago, President Donald Trump announced his intention to pull the United States out of the Paris Climate Agreement, a pact reached in Paris in 2015 in which nearly 200 countries volunteered a plan to curtail greenhouse gas emissions. 

“Climate change is a manmade problem, and we can create manmade solutions,” Natalie Barefoot, associate director of the Environmental Justice Clinic at UM’s School of Law, said in a recent Miami Law podcastthat came on the heels of the IPCC’s special report on global warming. “The issue is whether or not we will take up the mantle and actually do something about it.”

News@theU asked other UM experts to comment on rising greenhouse gas emissions and what we can do about them. Here’s what they had to say: 

Paleoclimate data show that atmospheric carbon dioxide levels are higher than they have been in the past 800,000 years. How are scientists able to determine past carbon levels from hundreds of thousands of years ago?

This comes from ice cores, mainly from Antarctica. Air bubbles that are trapped in the cores have remnants of ancient atmospheres, and hence we can directly measure what the CO2 concentrations were.

—Amy Clement, professor in the Department of Atmospheric Science at the Rosenstiel School of Marine and Atmospheric Science 

If we could somehow stabilize greenhouse gas emissions at the current rate, would global warming stop?

No. The climate system reacts to forcing with some delay. Think of a pot of water—it takes some time to heat up after you turn on the burner. Now imagine a pot of water 4,000 meters deep covering 70 percent of the globe. The global ocean has an enormous capacity, meaning that ocean temperatures and sea level will continue to rise for decades and even up to a century even for fixed emissions. The only way to reverse this is to reduce emissions.

—Amy Clement, professor in the Department of Atmospheric Science at the Rosenstiel School of Marine and Atmospheric Science 

Just how much will the Trump administration’s planned exit from the Paris accord hamper the our nation’s ability to decrease carbon emissions?

“It does not decrease at all our ability, but rather decreases our will, which is critical as the Paris Agreement does not place legally binding requirements to decrease emissions, but depends on the will, leadership, and commitment of individual countries. Under the agreement, the U.S. is responsible to report on our emissions, but that merely provides information on our progress, or in the case of this report, lack of progress, in meeting the goals of keeping global temperature increases below 2 degrees Celsius above preindustrial levels. 

Rather than being considered a treaty, which would need to be ratified through Congress, the United States had implemented its obligations under the Paris Agreement through Executive Orders such as the Clean Power Plan put in place under the Obama administration. These Executive Orders, which had been expected to allow the United States to meet its commitments under the Paris Agreement, have been repealed by the Trump administration. This recent report that U.S. emissions rose 3.4 percent rather than stayed the course or decreased demonstrates the incredible effect this decision and the federal government’s subsequent actions have had. In the U.S., 56 percent of our greenhouse gas emissions are from electricity and transportation; the federal government, through the executive branch and/or Congress, has an incredible capacity to move those sectors forward on a national level. We are now dependent on the many states and local governments who remain committed to the Paris Agreement targets to lead the way. However, by this recent report, their efforts at this moment do not seem to be sufficient to keep us staying the course.

—Natalie Barefoot, associate director of the Environmental Justice Clinic at UM’s School of Law 

What effect will the increase in greenhouse gas emissions have on human health?

Increased carbon dioxide emissions will have a devastating impact on human health. Carbon dioxide gas, one of the most abundant greenhouse gases, has accelerated the pace of global warming, which, in turn, has unanticipated consequences for human health. For example, the rise in temperatures and precipitation will result in more vegetation growth and spikes in pollen. And with that growth comes increases in the burden of allergies, asthma, immunological disorders, and other related conditions. Global warming will intensify the frequency of hurricanes and extreme weather events, such as flooding, drought, and tornadoes. Therefore, we will also see an increase in unintentional injuries related to those events. All of this will, of course, increase the disease burden and put more strain on our health care system. And we must be aware that along with CO2 emissions come other pollutants. For example, coal burning not only emits CO2 but also emits black soot and fine particulate matter—a mixture of solid particles and liquid droplets—and these emissions also directly affect cardiopulmonary health.

—Naresh Kumar, associate professor of environmental health in epidemiology and public health at the Miller School of Medicine 

What types of building strategies and practices need to be adopted to help reduce greenhouse gas emissions?

In South Florida, we can draw on the sun as a power source. Various options are increasingly feasible financially for individuals to convert to solar power, and there are conversations about micro-grids that could operate in neighborhoods. We can also reduce the need to heat and cool by simple and immediate strategies we can take individually—we can plant more trees to lower air temperature around buildings, install reflective or green rooftops, open the windows to capture and enhance air flow, look to daylight to limit the need for artificial light, and dry our clothes outside. 

Looking at how to retrofit and to assure that new buildings can passively heat and cool and don’t rely on power-driven mechanical systems for heating and cooling reduces the need for power. And then we can look to low-carbon materials in our buildings. We can re-use existing materials and limit the distance from which materials are sourced and travel.

—Joanna Lombard, professor in the School of Architecture  

What strategies and policies has the University of Miami adopted to become more sustainable and do its part to help reduce greenhouse gas emissions?

In 2007, we signed the American College and University Presidents Climate Commitment. This historic signing demonstrated the University of Miami’s dedication to sustainability and set an emission reduction target of 20 percent by 2020 from a 2007 baseline. As part of the Presidents Climate Commitment, the University of Miami was required to initiate two or more tangible actions to reduce greenhouse gases from the following list: 

  • Establish a policy that all new campus construction will be built to at least the U.S. Green Building Council’s LEED Silver standard or equivalent.
  • Adopt an energy-efficient appliance purchasing policy requiring purchase of ENERGY STAR certified products in all areas for which such ratings exist.
  • Encourage use of and provide access to public transportation for all faculty, staff, students, and visitors at our institution.
  • Participate in the Waste Minimization component of the national Recycle Mania competition. 

We adopted the implementation of all four of those actions. Under President Julio Frenk’s leadership, UM has joined the “We Are Still In the Paris Agreement” movement and continues to support climate action on our campuses.

—Teddy Lhoutellier, University of Miami sustainability manager