Last year the world had yet another confirmation that CO2 levels are rising.

“On May 2, after nightfall shut down photosynthesis for the day in Hawaii, carbon dioxide levels in the atmosphere touched 400 parts-per-million there for the first time in at least 800,000 years. Near the summit of volcanic Mauna Loa—where a member of the Keeling family has kept watch since 1958—sensors measured this record through sunrise the following day. Levels have continued to dance near that benchmark in recent days, registering above 400 ppm for the first time in eons after midnight on May 7. When the measurements started the daily average could be as low as 315 ppm, already up from a pre-industrial average of around 280 ppm.” (

That was a year ago. But this year we are back again, and sooner. And the expectation is that next year we will hit 400ppm again, and sooner, and for more days.

In one sense nothing has really changed. We know CO2 levels are increasing but round numbers act like a line in the sand and when we cross them, they highlight the problem.

Want to test CO2 yourself?

It’s now possible to monitor CO2 levels with an affordable desktop unit. The KeepAlert range has both a display only ($160) and logging version ($240). They are intended for monitoring CO2 in rooms such as meeting rooms, offices, houses and factories, but could easily be used (with sufficient protection) to monitor outside conditions.

Schools could easily run their own experiment to see what is happening to the CO2 levels in their own area. If a school is interested in a unit please contact us for discounted prices. We just ask that you provide us with a couple of experiments or results so that we can add them to our collection of experiments.