Weighing Carbon: Understanding Global Emissions

Scientists and media around the world constantly cite our need to reduce our global greenhouse gas emissions. But how do we take this abstract measurement of carbon emissions and turn it into something we can understand, and therefore, reduce?

Greenhouse gas emissions, specifically carbon dioxide emissions, are talked about in largescale quantities with units of measure that we don’t typically use in everyday life. This can make digesting information about climate change and energy use inaccessible and add additional barriers to those trying to take part in the climate movement. Taking time to learn and contextualize the language and scale when talking about carbon emissions can be time consuming and difficult, so we’ve done it for you.

That weighs a ton!

The base unit of measure for carbon emissions is a ton, or roughly the size of an adult male walrus. The average carbon footprint of a person in the United States is 16 tons per year. This is a helpful start, but thanks to fossil fuel-based economies, we actually have billions of tons of carbon to account for since the dawn of the Industrial Revolution. Scientists use terms such as megaton (one million tons) and gigaton (one billion tons) to talk about these vast quantities more concisely. Humans have a difficult time contextualizing large quantities such as these, so it’s normal if these numbers don’t resonate with you. Picture a hot air balloon. If you add up all the emissions from industry, energy use, transportation, agriculture, and individuals in the U.S. in 2021, you’d get 6.34 gigatons—or a little over 6 billion hot air balloons—per year.

How do these emissions affect us?

Globally, humans release roughly 35 gigatons—or 35 billion hot air balloons—of carbon dioxide annually. Other human-driven changes such as deforestation, habitat destruction, soil and water contamination, and monoculture farming have also altered the climate and affected the Earth’s capacity to absorb and store carbon, meaning the natural carbon cycle is overwhelmed. This has created climate change as we know it today—a seemingly endless cycle of damaging floods, uncontrollable wildfires, multi-decade droughts, and deadly heat waves that seriously harm wildlife and people.

How does nature help us?

Carbon dioxide is naturally drawn in and stored in trees, vegetation, water, and soil. Natural climate solutions—such as planting trees, building living shorelines, and restoring degraded lands—harness nature’s inherent ability to do this. However, we’d need large swaths of land to fully deploy these nature-based carbon sequestration practices at the scale required to balance global emissions, and we don’t quite have that anymore. For example, forests and grasslands in the U.S. can store more than 10 percent of the country’s annual greenhouse gas emissions, or 140 million tons each year. But as climate-fueled wildfires are wiping out considerable acres of forest—about 25 million acres since 2020 in the U.S. alone—it’s proving more difficult to rely solely on nature-based solutions.

Photo credit: Irina Iriser

Where can we fill in the gap?

Industry is one of the biggest polluters that we must decarbonize. Industrial processes account for 24 percent of the United States’ total carbon dioxide emissions. Most of that comes from the burning of fossil fuels. Addressing pollution from the industrial sector is critically important in our path to lowering climate-disrupting greenhouse gasses. Luckily, we have technologies that can be used to drastically reduce the emissions involved in these hard-to-abate industries—like steel and cement production—where fewer decarbonization alternatives exist.

These technologies either capture carbon at a point source, like on top of a smoke stack, or from the ambient air. In both instances, we can permanently sequester the captured carbon underground or reuse it in industrial processes. Direct air capture (DAC) facilities that remove CO2 from the air have begun to operate across the world. Currently there are 18 facilities across the United States, Canada, and Europe and collectively capture around 10,000 tons of carbon annually, with larger scale DAC facilities on the way. The United States Department of Energy just announced two commercial scale DAC plants, referred to as DAC Hubs, with the capability to capture 1 megaton of carbon annually in the mid to late 2020’s. The International Energy Agency’s Net Zero by 2050 plan allocates more than 85 megatons of capturing power to DAC plants by 2030 and around 980 megatons of CO2 in 2050, which would be a vast increase from current capacities.

However, the deployment of these carbon capturing technologies requires a number of things: robust community engagement and participation, cumulative impacts analyses, energy sources, and lifecycle analyses. The point of these solutions is not to allow fossil fuel companies to continue polluting, but rather focus using them to decarbonize our economy, especially in sectors that are difficult to decarbonize such as cement production. In fact, thousands of everyday products, like reusable water bottles and sunglasses, are made using oil, gas and processes that create CO2 emissions. These technologies are vitally important to reducing the nearly 8 billion tons of CO2 that come from these processes annually in addition to the CO2 that has been building up in our atmosphere.

There is not one perfect solution to address the impact that carbon emissions are having on our changing climate, but there are many helpful tools that can address emissions from different sectors to create a well-rounded and multifaceted emissions reduction strategy.