IEA Greenhouse Gas R&D Programme


The jet stream wobble and what it means.

67 JG imageI like to watch the weather in a morning on BBC news to start the day. These days we regularly get images of the flow of the jet stream and I have been amazed by how much it varies, wobbling around the upper region of the globe. This morning we were told that the jet stream was bringing high winds to the UK and planes coming from the USA will be swept over the Atlantic with its force. Sounds like going the other way might take you a lot longer !!!

Then as I read the newspaper the wobble in the jet stream i understand is due to the Arctic ice melting. The melting ice, which is caused by global warming, exposes dark ocean beneath, which absorbs more sunlight than ice and warms further. This feedback loop is apparently why the Arctic is heating up much faster than the rest of the planet. As a result the temperature difference between the Arctic and lower latitudes is narrowing. This is the crucial bit as it is this temperature gradient between them that drives the jet stream wind. So the good old jet stream forms a boundary between the cold north and the warmer south, and the lower temperature difference means the winds are now weaker (although not today!!). This means the jet stream meanders more, with big loops bringing warm air to the frozen north and cold air into warmer southern climes. Another consequence of the weaker jet stream is that is can get stuck over regions for days and weeks which can bring extreme cold periods to our shores.

Who says global warming isn’t happening !!!