Helping Nature Get Rid of Methane
Methane is released into the air through both natural and man-made processes. Nature also breaks down methane in the air, so that normally the level would maintain safe conditions for life. Unfortunately the natural process cannot take care of the excess methane from human activity, which means the extra methane traps heat we wish it didn’t.
But since nature already has processes for taking breaking down methane, what if we could expand one of those processes? That is what we are doing at Blue Dot Change. Specifically, we are expanding the process nature uses in the air above the oceans.
The ocean air is a great place to do this. We don’t think of them a lot, since we live on land, but oceans cover about 3/4 of our planet’s surface, which gives us a lot of room to work with.
How does nature do it?
The element nature uses to break down methane over the ocean is chlorine, which is a component of salt. If you’ve ever been in the ocean you know it’s salty! The picture above shows you that the ocean throws up a lot of elements (referred to here as “ions”) and molecules into the air above it. The ones of interest to us are chlorine ions and other reactive molecules such as nitrogen oxides, collectively referred to as “NOx”.
If you look again at the picture, you’ll see a bubble that shows a chemical reaction: methane being broken up. Sunlight (specifically “uv sunlight”) provides the power for the chlorine to rip the methane apart. At the end of the process, the methane molecule is gone, and instead we have two water (H2O) and one CO2. Both also have climate impact, but much less intense than methane!
There’s one last element: dust. The wind picks up dust and blows it over the oceans (for example, dust from the Sahara blows across the Atlantic and fertilizes the Amazon). While traveling over the ocean, iron in the dust acts as a catalyst (a chemical that participates in a reaction and then is restored at the end to do so again). In this case it’s a catalyst for chlorine reactions that break down methane.
So, looking at all that together: we will be providing a catalyst, an iron chloride, into the air above the ocean, to expand the process nature already uses.
Read on for more details of how we will do it. If you would like further details on the chemistry, click here. If you would like to know more about safety and cultural issues, click here.
OK, so once we know what we want to do, how do we do it? Since we’re working over the ocean, clearly the thing to do is dispense the catalyst from a ship. In our case, we will use commercial ships that already travel over the ocean.
A ship is a good platform not only because it is already traveling. Every cargo ship has a smokestack, and even with today’s cleaner fuels and equipment, those smokestacks emit some of the compounds (like NOx) that participate in the catalyzed reactions. So by adding the catalyst to the flue gas, we will have an ideal environment, similar to the one just above sea level, but more concentrated, in which to break up methane.
Based on the ocean environment, the catalyst is expected to stay in the air for up to ten days, depending on weather conditions.
A flue stream has other advantages. For example, the USA Environmental Protection Agency has developed models of smokestack emissions behavior that can be used to model the spread of our catalyst as well, for both performance and safety reasons.
Although the ocean and atmosphere are vast, they are affected by human activity. In fact that is what we want: to affect the amount of methane in the air! But when you take a headache tablet, you know it could have other effects on your body. The same is true of atmospheric work.
Before doing any work outside the lab we will be providing safety studies to US and other regulators. There are two primary areas to concentrate on. The first is the effect of adding iron to the ocean. Our calculations show that the amount we will release will not be enough to have any effect. The other is if any catalyst might travel over an inhabited region. Again, it appears any effect is negligible. Regardless of our current calculations, we will be doing formal studies and supplying those for review and approval before beginning any work in the atmosphere.