Earth’s love-hate relationship with carbon dioxide

Landing shadowAt last month’s international Pint of Science Festival, the Grantham Institute co-sponsored three events themed around Planet Earth. SSCP DTP student Rachel Bertram, who organised several of the talks, summarises some of the discussions about carbon dioxide, the most well-known greenhouse gas.

Over a few nights each May, Pint of Science brings scientists out of their universities and research environments to the local pub where they give talks to the general public about their latest research in a friendly and relaxed setting. This year, they covered diverse themes, ranging from ‘Beautiful Minds’, to ‘Atoms to Galaxies’, to ‘Tech Me Out’. One of our ‘Planet Earth’ evenings focused on carbon dioxide and the love-hate relationship different aspects of our planet have with this greenhouse gas.

“Aviation is actually a victim of climate change, as well as being a partial cause”

Professor Paul Williams, from the Department of Meteorology at the University of Reading, started the evening by looking at the impact of climate change on air travel, explaining how “aviation is actually a victim of climate change, as well as being a partial cause”. Although aviation contributes less than 1% of global carbon dioxide emissions, climate change will have dramatic impacts on the aviation industry − and some of these might even have started already.

Rising sea levels and storm surges will threaten coastal airports, often located not much higher than present day sea level. For example, San Francisco and New York’s JFK airports are both only 4m above sea level, while others, such as Schiphol, Amsterdam, are actually below sea level! In addition, the jet stream, a narrow band of fast flowing air, is expected to strengthen by 15%, which could increase the frequency of turbulent events. Paul’s climate models show that flight times will change as a result of this strengthening atmospheric circulation. He suggested that the chance of a flight from London to New York taking over seven hours will increase by 80% within the next few decades. As a result planes will spend more time in the air, burning more fuel, emitting more carbon dioxide and hence contributing further to climate change. In fact, this may already be happening – Paul told us of two recent flights that had to make unscheduled stops for refueling whilst crossing the Atlantic!

Pint of Science - talk

The tiny pin-head plant that has a big impact on the world’s oceans

For our second talk of the evening, Grantham Affiliate Dr Susan Little focused on the oceanic response to carbon dioxide, giving a talk entitled “Bloom and Bust: Glassy diatoms impact global ocean nutrient distributions”. Susan’s research focuses on diatoms, tiny pin-head sized plants that thrive during summer in the Southern Ocean that surrounds Antarctica.

Like other plants, diatoms create their energy by utilising sunlight in a process called photosynthesis, which takes in carbon dioxide. In the summer months, increased light and nutrients mean diatoms ‘bloom’ and take up most of the nutrients in the upper layers of the ocean. Once these nutrients are depleted, the diatom cycle shifts to the ‘bust’ phase, where they die and sink to the bottom of the ocean. As they sink, the carbon dioxide and nutrients they incorporated are released into the deeper waters, which become enriched in nutrients such as zinc and silica. Carbon dioxide can be stored in these depths for hundreds or thousands of years. Currents in the Southern Ocean transport the surface waters away from the Polar Regions towards the equator, effectively trapping the enriched waters below. This phenomenon robs nutrients from other areas of the world’s ocean − one organism, thriving in one area, has a big impact on global oceanic cycles.

Read more about carbon dioxide – the good and the bad, the right and the wrong.

Pint of Science - oceans

Organising Pint of Science was a pleasure. My favourite part was seeing captivated, engaged audiences full of people who hadn’t necessarily thought about these topics before. Personal highlights included a school teacher asking for more information to incorporate into her lessons, and someone who described themselves as “allergic to science” having a “fantastic evening”! I truly believe that everyone took a new bit of knowledge away with them each night of the festival; whether that was the audience members, a speaker listening to another’s talk, myself and the other organisers or the people staffing the bar!

Pint of Science will be back next May with more fascinating talks spanning a wide range of science – look out for updates. In the meantime, I’d like to thank everyone who attended our events and made them so successful; the brilliant speakers; our sponsors Elsevier, Grantham Institute − Climate Change and the Environment and the EPSRC Centre for Doctoral Training (CDT) in the Mathematics of Planet Earth (MPE); everyone involved in organising these events from Imperial; and the Hand and Flower pub in Hammersmith for hosting us.

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