Watching Earth Breathe

Daily carbon dioxide concentration measurements for the year to May 2013. Daily measurements are shown as black dots, weekly averages as red lines, and monthly averages as blue lines.  On May 9th 2013, the daily value exceeded 400 ppm.

Daily carbon dioxide concentration measurements for the year to May 2013. Daily measurements are shown as black dots, weekly averages as red lines, and monthly averages as blue lines. On May 9th 2013, the daily value exceeded 400 ppm. Click for larger graph: Graphic is from NOAA Mauna Loa Observatory

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.

The annual cycle of carbon dioxide measurements at Mauna Loa plotted with the trend subtracted against month of the year. The data is colour-coded.

The annual cycle of carbon dioxide measurements at Mauna Loa plotted with the trend subtracted against month of the year. The data is colour-coded and stupidly I have used the same colour for the 2010’s as the 1970s (Doh!). But even so it looks to me like this cycle is unchanged

However the rate at which we are emitting CO2 is increasing. No news here 😦

The annual increase in annually averaged CO2 concentration. Back in eth 1970s the annual incerase were just over 1 ppm per year. Now they are 2 ppm per year and above. The rate of increase is around 0.23 ppm per year per decade.

The annual increase in annually averaged CO2 concentration. Back in the 1970s the annual increase about 1.5 ppm per year. Now it is more typically 2 ppm per year and above. The rate of acceleration is around 0.23 ppm per year per decade.

Tags: ,

2 Responses to “Watching Earth Breathe”

  1. Nick Day Says:

    Breath -> Breathe?

  2. protonsforbreakfast Says:

    Ooops. Thanks.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: