The Other Half of Warming

Hi there,

We’re Overview Capital and we invest in the mitigation of methane and other super pollutants at the earliest stages. Welcome to the eighth edition of our newsletter, The Overview: Our biweekly dispatch on the world of methane and other super pollutants.

Today, we’re surveying the broader world of super pollutants beyond methane as the White House moves to support monitoring and mitigation approaches for greenhouse gasses like nitrous oxide, HFCs, and more.

The topline

There’s no shortage of political noise these days, so we’re here to cut through it to provide the most relevant updates on methane and super pollutants. Last Tuesday, the Biden Administration announced new efforts to accelerate the detection, monitoring, and mitigation of what the White House calls "super pollutants." 

At Overview, we use the term “super pollutant” to represent “short-lived” atmospheric pollutants which are Methane, Tropospheric Ozone (O3), Carbon Monoxide (CO), Volatile Organic Compounds (VOCs), Fluorinated-gasses/hydrofluorocarbons (HFCs), Nitrous Oxide (N2O), and Black Carbon, that have a shorter atmospheric lifespan than CO2 but have a larger warming impact in that timeframe. We believe the terminology does an excellent job of cutting to the core of what differentiates greenhouse gasses like methane and nitrous oxide from carbon dioxide. 

While carbon dioxide is the largest single driver of global warming over long timeframes, accounting for roughly half of observed global warming since the Industrial Revolution, other greenhouse gasses are often much more potent – pound-for-pound – than carbon dioxide is over shorter time frames.

What are the other super pollutants?

Methane (CH4)

There is 200x less methane in the atmosphere than there is carbon dioxide. Yet, methane has driven roughly 30% of global warming compared to carbon dioxide's 50%. Part of the reason for this is that atmospheric methane levels have increased more relative to carbon dioxide concentrations; methane concentrations have more than doubled over the past two centuries, whereas carbon dioxide levels are 'only' up 50% or so.

Further, on a molecule-for-molecule basis, methane is a much more potent warming driver than carbon dioxide. Sources of human-caused methane emissions span agriculture, oil and gas, and other waste streams like wastewater treatment or landfills.

Nitrous Oxide (N2O)

While methane is roughly 28 times more potent than carbon dioxide over a 100-year timeframe and 84 times more potent than carbon dioxide over a 20-year timeframe. Nitrous oxide is even more potent than methane, with a striking ~265 times higher global warming factor than carbon dioxide over 20 years.

Nitrous oxide emissions predominantly stem from agriculture and soil management as well as fossil fuel combustion. The majority of human-caused nitrous oxide emissions are a result of the application (and overapplication) of nitrogen fertilizers, which 'feeds' microbes that produce nitrous oxide. Similarly, nitrogen in manure and urine from livestock also often breaks down into nitrous oxide. Combustion of fossil fuels also produces nitrous oxide alongside carbon dioxide. If you've heard of catalytic converters being stolen from cars over the past five years, those converters exist to mitigate nitrous oxide emissions at their source, namely the tailpipe in this case. Combustion of jet fuel in aviation is also a significant source of nitrous oxide emissions.

Fluorinated Gasses / Hydrofluorocarbons (HFCs)

Hydrofluorocarbons were also a focal point of the new White House release. They are synthetic greenhouse gasses used primarily as refrigerants and solvents in the production of insulating foams and packaging materials. HFCs were originally created to replace chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), which, if you remember the ozone layer drama from two decades ago, were primary culprits in ozone depletion. While the Montreal Protocol, ratified in 1987, stands out as one of the most successful climate policies of all time, as it successfully coordinated efforts to phase out CFCs and HCFCs in favor of HFCs, HFCs still drive global warming when they leak from refrigeration systems, air conditioners, heat pumps, or from places where products they're used in are manufactured. For instance, Chinese manufacturers have come under scrutiny in recent years for significant HFC releases in violation of international treaties.

Similarly to methane, for which there are increasingly many voluntary commitments targeting emissions reduction, for HFCs, the Kigali Amendment is an international agreement to phase out HFCs by 2100, which could help avoid up to 0.5°C of global warming.

Tropospheric Ozone (O3)

While humans and other living beings benefit from stratospheric ozone, which protects us by absorbing harmful ultraviolet radiation, tropospheric ozone (O3) is a harmful air pollutant found in the lowest layer of Earth's atmosphere, the troposphere. When you hear people talk about air pollution, like smog, tropospheric ozone is often a key component of it and poses significant health risks to human respiration and our cardiovascular systems. 

The main sources of tropospheric ozone are not direct emissions but photochemical reactions that turn ‘precursor pollutants,’ like methane, nitrogen oxides (NOx), and volatile organic compounds (VOCs) into tropospheric ozone. These precursors are emitted from various sources, including fossil fuel combustion in power plants and cars, industry, and agricultural activities. When hit by sunlight, these chemicals can react to turn into ozone.

Carbon Monoxide (CO)

Carbon monoxide, like other greenhouse gasses, is colorless, odorless, and tasteless. In addition to driving global warming, it’s highly toxic to humans and animals. While not itself a ‘direct’ greenhouse gas, it influences the concentration of other greenhouse gasses and can accelerate their warming impact. Hydrogen is a similar ‘augmenter’ of other greenhouse gasses. For instance, as explored above, carbon monoxide is a tropospheric ozone precursor. 

Carbon monoxide sources are predominantly fossil fuel production, as incomplete combustion of fuels like gasoline, natural gas, oil, coal, and wood can yield carbon monoxide. Cars are the largest source of carbon monoxide, especially in urban areas. Other sources include residential heating systems, heavy industry, and wildfires.

Volatile Organic Compounds (VOCs)

Like carbon monoxide, volatile organic compounds aren’t a direct greenhouse gas but they are insidious for human and animal health. They comprise a large group of organic chemicals that share a high vapor pressure at room temperature, which means they evaporate easily into the air. Like carbon monoxide, human-caused VOCs are predominantly produced by cars, as well as in chemical manufacturing processes. Their emission can also stem from the use of products like adhesives, cleaning agents, and pesticides. VOC exposure can cause health problems like respiratory issues, headaches, and eye irritation. VOCs, like carbon monoxide, are also significant ozone precursors.

Black Carbon

Black carbon is fine particulate matter produced by the incomplete combustion of fossil fuels and biomass like wood. Black carbon particles are a main component of soot and absorb sunlight, meaning they contribute to global warming and climate change. For instance, when black carbon and soot settle on ice and snow, it reduces the natural albedo (reflectivity) of the underlying ice and snow, accelerating melting and contributing to global warming. Soot and black carbon from wildfires can also travel thousands of miles; black carbon from recent Canadian wildfires was found as far away as Antarctica in recent years.

Emissions of black carbon come both from sources like wildfires, burning of excess biomass in agriculture (think rice farming, for instance), and from fossil fuel combustion, especially in diesel engines. Like many other super pollutants, black carbon is bad for human and animal health, contributing to respiratory and cardiovascular diseases.

What’s in the White House release?

On Tuesday, the White House hosted a 'Super Pollutants Summit' with U.S. officials, companies, environmental organizations, and more to "announce new domestic and international actions to tackle climate super pollutants and celebrate successes in reducing super pollutants to date…"

The highlighted initiatives spanned efforts from the detection and monitoring of super pollutants to mitigation strategies. One example is United Airlines and NOAA announced a new partnership to equip commercial airliners with tools to aid in the detection and monitoring of super pollutants, including methane and carbon monoxide. Another, the Bezos Earth Fund announced $10 million in funding to support MethaneSAT, a methane monitoring satellite we covered in depth in edition three of this newsletter, to advance satellite-based methane emissions detection.

On the mitigation front, the EPA's work was highlighted, including a national program the agency is advancing to reduce HFC use by 85% by 2036. This effort could yield emissions reductions "equivalent to 4.6 billion metric tons of carbon dioxide from 2022 to 2050—equal to approximately three years of U.S. power sector emissions at 2019 levels."

Further, Ascend Performance Materials, a chemicals manufacturer, announced it would install another thermal reduction unit in one of its U.S.-based facilities. Ascend Performance Materials has been successful in demonstrating its technology's efficacy in eliminating nitrous oxide emissions in its industrial operations.

There's a whole lot more in the release that was discussed at the summit yesterday, which underscores just how much work there is to do and how much opportunity there is in super pollutant work and investment. You can explore more from the summit and release here.

Our super pollutant ‘policing’ companies

Several Overview Capital portfolio companies stand to benefit from enhanced public and private sector focus on detecting and mitigating super pollutants:

• Miraterra: By ushering in exponential improvements in soil measurement, Miraterra helps farmers mitigate nitrous oxide emissions while saving money on fertilizers.

• Bluedot: By helping fleet operators transition to EVs, Bluedot helps mitigate nitrous oxide emissions from internal combustion engines.

• ReynKo: By solving previously unsolved challenges in modeling turbulent flows, Reynko helps industries like aviation make flight routes more efficient, reducing nitrous oxide emissions (Aircraft face turbulent resistance during flight, particularly at higher speeds. Overcoming this resistance burns a lot of fuel.)

• Mojave: By building better HVAC systems, Mojave helps reduce HFC use and emissions.

If you're interested in learning more about these businesses, we're happy to connect you.

The bottom line

Carbon dioxide emissions are far from the only character in the global warming story. It's roughly only half the story and less than that over shorter time frames. As much as we focus on methane in this newsletter and our investing work, methane isn't the only character on stage. However, since it’s responsible for a third of current warming and receives <2% of climate funding, it is the best lever we have to slow warming today. That being said, other greenhouse gasses and radiative forcers (things that alter the Earth's energy balance by affecting the amount of incoming solar radiation or the amount of outgoing infrared radiation emitted by the Earth), ranging from nitrous oxide to HFCs, tropospheric ozone, and even water vapor, all have a part to play in heating the planet. This means mitigation and management of other super pollutants in addition to methane is all part of the layered approach to restabilizing a changing climate.

News and Policy

• Day after day, the world continues shattering global heat records. Both Sunday and then Monday were likely the hottest days on Earth in 100,000 years.

• Ashgrove, a Tasmanian dairy producer, is testing consumer demand for lower-methane dairy, which it is now marketing on store shelves after using feed additives to reduce methane emissions from a fifth of its herd so far.

• New studies suggest we’ve collectively under-appreciated the role of tree bark in reducing methane levels in the atmosphere, which could have implications for calculating the benefits of reforestation and avoided deforestation projects (among many other things). Trees may play close to if not as large a role as soils in reducing atmospheric methane.

Odds and Ends

We're encouraged by how rapidly the conversation around all super pollutants is shifting, as evidenced by the White House release last week. We have many people to thank, including our friend, Ilissa Ocko, Senior Advisor for the U.S. Special Presidential Envoy for Climate at the Department of State, who is driving this conversation forward. She has a fantastic TED Talk on methane that we suggest watching for deeper learning. Additionally, change cannot happen without technological innovations from the wonderful companies we highlighted above, some of which we're proud investors. Super pollutants drive over 50% of current warming: The time to address them is now.

Thanks for reading the eighth edition of The Overview. If you are a methane or super pollutant focused company or want to connect on methane or our investment work, please reach out to [email protected].

– Team Overview