In my work, I make measurements of both carbon dioxide (CO2) and oxygen (O2) in the atmosphere. These measurements help us to understand the global carbon cycle, and this information can then be used by climate scientists to help predict future climate change. Then the results of our research can be used by the governments of the world to hopefully make the right decisions for maintaining a healthy planet that our children will inherit from us.
Humans are putting huge amounts of CO2 into the air from our use of “fossil fuels”: coal, petrol and oil, and natural gas. We use these fossil fuels to run our cars, buses, lawnmowers, and to make electricity. This means that every year we add about 6 billion tonnes of CO2 to the atmosphere. This CO2 is a “greenhouse gas”. This means that each molecule of CO2 has a physical property allowing it to absorb infra-red heat energy. After absorbing this energy, the CO2 molecule will then release it again; some of the released energy will be reflected out to space, but some will be sent back to the surface of the Earth, resulting in a small warming of the Earth’s surface.
The total amount of CO2 in the atmosphere is very small: for every one million molecules of air, only 370 of them are CO2 molecules. However, this very small number of molecules has a huge impact on our climate. If we removed all of the CO2 from the air, average temperatures on the Earth would decrease by about 9°C. So obviously, having some CO2 in our air is a very good thing! And you might think that it would be quite nice if the temperature became a bit warmer than it is now. For some places in the world this may be true, but in general, scientists believe that a warmer climate has many more bad consequences than good.
In any case, my research is not concerned with debating this point, but instead I focus on a better understanding of the carbon cycle. In the last 150 years, since we have been using fossil fuels, we have increased the CO2 concentration in the air from 280 parts per million (ppm) to 370 ppm, an increase of over 30%. More importantly, we are using more and more fossil fuels everyday, so in the next 100 years, we expect the CO2 concentration to increase to somewhere between 550 and 1000 ppm. This large range, from 550 to 1000 ppm, depends partly on our predictions of how much fossil fuels we will use in the future, but it also depends heavily on how the Earth responds to our input of CO2 into the atmosphere. The very interesting fact is that of the 6 billion tonnes of CO2 we put into the atmosphere each year, only about half of it stays in the atmosphere. About one quarter dissolves into the world oceans, and the other quarter is taken up by the plants and forests of the world.
Even more interesting is that how much CO2 stays in the atmosphere, dissolves into the oceans, or is taken up by plants, is highly variable from one year to the next. Trying to understand the reasons for this variability is one of the main focuses of my work. I will measure the atmospheric CO2 and O2 concentrations onboard ships crossing the North Atlantic Ocean. The North Atlantic is very important to the world’s ocean circulation patterns (at least this part of the movie The Day After Tomorrow was scientifically correct). By measuring O2 in the atmosphere, I hope to investigate whether O2 is being released from the ocean. If so, this could suggest mixing changes in the North Atlantic as a response to climate change. The North Atlantic is also an area which is a strong sink for atmospheric CO2, therefore, by making my measurements, we will be able to watch for possible changes in the size of this sink. Finally, improving our understanding of the carbon cycle in the North Atlantic, puts us in a position to better understand the sink for atmospheric CO2 by the land plants on the European continent. Such an understanding has become very important to national governments, now that the Kyoto Protocol has come into force.