Peter Girguis - The methane cycle and the challenge of global warming

Peter Girguis, Professor of Organismic and Evolutionary Biology at Harvard University, describes methane and the uncertainty of its effects on Earth.

About Peter Girguis

"I’m a Professor of Organismic and Evolutionary Biology at Harvard University.

My research focuses on the deep sea and the relationship that animals and microbes have to one another, but also to their environment. We do a lot of work developing new tools to make measurements that we couldn’t make before. I do so with an eye towards democratising science, with a hope that all have an opportunity to study the deep ocean."

The methane cycle

Here on Earth we have a number of different cycles. Most of us are familiar with the water cycle, for example, or the oxygen cycle. Methane is a cycle that is really important not only on Earth today, but also in Earth’s past. Let’s start with methane. What is it? Methane is a molecule that we use as a fuel. So whenever you light your stove or barbecue you are burning, in part, methane. It’s an interesting molecule because it is so robust. It’s a carbon and four hydrogens that are covalently bonded, which makes it incredibly stable. In other words, if you were to bottle up methane in a glass ampule and leave it on the bench, it would be stable for a very long time; it doesn’t react very quickly.

Key Points

• Most of us are familiar with the water cycle, for example, or the oxygen cycle. Methane is is a potent greenhouse gas and its cycle is really important not only on Earth today, but also in Earth’s past.
• Methane is a stable molecule that can be broken down for fuel, but it’s also a potent gas that may contribute to rapid climate change. The majority of methane is produced by microbes in the deep sea.
• If we get to the point where the heat that we are seeing in our atmosphere and upper ocean warms up enough of the deep sea, we are going to be releasing gigatonnes of methane into the ocean and we don’t know what’s going to happen.
• As we study methane cycling in the deep sea, we do put some thought into what could possibly happen at these seeps, especially as it relates to our human activities and the role we’ve played in warming the atmosphere in the upper ocean.
• It is critical that we as humans stop thinking of ourselves as being separate from the natural world. The deep sea is 80% of our planet’s living space and remains largely mysterious yet profoundly essential for the well-being of living things on Earth.