The Keeling Schadenfreude Game

This graph shows the increase in atmospheric CO2 since 1958. It's probably the best proxy measurement of how we are changing the Earth's climate. The higher number, the warmer we are going to get.

and over the last two years.

It goes up in the northern winter and then drops back in the summer as the great northern boreal forests do their photosynthesis. The increase from one year to the next is our bit from burning fossil carbon in the coal, oil and gas. It's been going up by a couple of ppm per year with the rate increasing slightly. About half the CO2 is absorbed by the oceans, making the water more acid, and the rest stays in the air, mostly for centuries and millennia.  If we are to avoid global warming and ocean acidification we must stop the increase, reverse it and reduce back to the 300 level. Our current activity continues to increase it.

Now here's the Keeling's Schadenfreude Game.

You have to guess what the peak CO2 concentration will be in May 2018.  We'll use the weekly average figure from the data supplied by Scrips from the Mauna Lao observatory, where Charles Keeling first made his observations.

Here are some numbers to help guide your guess, the peaks for the last half dozen years:

Mauna Loa data from Scrips : http://scrippsco2.ucsd.edu/data/atmospheric_co2/primary_mlo_co2_record
Date of maximum	PPM CO2	Increase from previous year
12/05/2012	397.28
25/05/2013	400.22	2.94
31/05/2014	402.12	1.9
23/05/2015	403.85	1.73	(La Niña)
28/05/2016	407.92	4.07	(El Niño)
20/05/2017	410.18	2.26

What will the 2018 figure in this record be?

Give your forecast to 2 decimal places.

For the record, I'm guessing 412.74 

See if you can get closer. Send us your guess by posting in the comments below or posting it on facebook in the Climate Geek Group https://www.facebook.com/groups/ClimateGeek/ or send a tweet, using #KeelingGame to 

Biff Vernon #FBPE @transitionlouth

The Winner will be announced at the end of May.