On May 9th 2013, the observatory at Mauna Loa in Hawaii recorded a single daily reading of carbon dioxide concentration of 400.3 parts per million (ppm) – the highest value since human beings have existed as a distinct species.
This is a bit depressing for reasons we are all familiar with, but on the bright side, the annual average won’t exceed 400 ppm until 2015 🙂
I took the opportunity to look at the Mauna Loa data again – it is freely available – because I found the annual cycle rather curious. The graph at the head of the page shows the Earth ‘breathing’ – absorbing CO2 from May to October (Northern hemisphere summer) and then emitting it again from November to May.
The daily variations are interesting showing lots of systematic increases and decreases, presumably reflecting imperfect mixing of CO2 in the weather in the central Pacific ocean
You can see that the concentration from May 2012 to May 2013 has increased by around 3 ppm – that’s our carbon dioxide emissions – but I wondered if the annual cycle of ‘breathing’ had changed over the years. After a little bit of Excel jiggery -pokery I found to my relief and surprise that there was no evidence of this. I think this means that Earth is still ‘breathing’ OK.
However the rate at which we are emitting CO2 is increasing. No news here 😦