by Judith Curry
The United States and five other countries agreed this week to fund an effort to cut emissions of methane, soot and other pollutants to start to slow the rate of human-induced climate change.
Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security
Abstract. Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids 0.7 to 4.7 million annual premature deaths from outdoor air pollution and increases annual crop yields by 30 to 135 million metric tons due to ozone reductions in 2030 and beyond. Benefits of methane emissions reductions are valued at $700 to $5000 per metric ton, which is well above typical marginal abatement costs (less than $250). The selected controls target different sources and influence climate on shorter time scales than those of carbon dioxide–reduction measures. Implementing both substantially reduces the risks of crossing the 2°C threshold.
U.S. Secretary of State Hilary Rodham Clinton has made the following remarks:
The Climate and Clean Air Coalition will spread practical ideas and practices regarding so-called short-lived pollutants, which remain in the atmosphere only for a short time – pollutants such as methane, black carbon or soot, hydrofluorocarbons. More than one-third of current global warming is caused by short-lived pollutants. They also destroy millions of tons of crops every year and wreak havoc on people’s health. Millions die annually from constantly breathing in black carbon soot that comes from cookstoves in their own homes, from diesel cars and trucks on their roads, from the open burning of agricultural waste in their fields. Furthermore, methane – a greenhouse gas more than 20 times more potent than carbon dioxide –can also be an abundant source of energy if we capture it instead of just venting it into the air or flaring it.
By focusing on these pollutants – how to reduce them and, where possible, use them for energy – we can have local and regional effects that people can see and feel. They can see those effects and become convinced that this commitment is one we all must all undertake. There will be better health, cleaner air, more productive crops, more energy – in addition to less warming. The UN Environment Program has determined that reducing these pollutants can slow global warming by up to a half degree Celsius by 2050.
Now, exceptional work has already been done to investigate how to reduce these pollutants. For example, UNEP has identified a package of 16 major actions, which include replacing inefficient cookstoves and traditional brick kilns with more efficient ones to cut down on black carbon, stopping the burning of agricultural waste, harvesting coal mine methane, improving wastewater treatment, and adopting emissions standards on vehicles.
Now, every one of the actions has already been applied somewhere, and so we know they work. Every one is based on existing technology, and fully half of them are considered low-cost interventions. So when you put all these factors together, they add up to an important opportunity that we cannot miss.
This coalition – the first international effort of its kind – will conduct a targeted, practical, and highly energetic global campaign to spread solutions to the short-lived pollutants worldwide.
One of the benefits of focusing on pollutants that are short-lived is, if we can reduce them significantly, we will have a noticeable effect on our climate in relatively short order.
Now, this project holds a lot of promise, especially in the context of our larger battle against climate change. There is no way to effectively address climate change without reducing carbon dioxide, the most dangerous, prevalent, and persistent greenhouse gas. So this coalition is intended to complement – not supplant – the other actions we are, and must be, taking.
JC comments: This is interesting on a number of fronts.
First, this is a good example of a no-regrets policy, one that is relatively inexpensive with ancillary benefits for human health and development. I suspect that political opposition to this should be pretty small, at least relative to political opposition to stabilizing CO2.
Second, walking before you run is a good strategy. Lets see if we can actually influence the climate in the expected way by reducing the methane and black soot. Not to mention exercise and test the efficacy of international cooperation and actions to reduce greenhouse gases.
Third, this would provide a very interesting short-term climate experiment to test our models and understanding.
So, does anyone see problems with this plan? Looks like win-win to me.