Please Don't Exhale

When I started teaching at Hall High School, I found an exercise to help students practice their graphing and analysis skills.

Using data from the Carbon Dioxide Information Analysis Center's sensors on Mauna Loa in Hawaii, the exercise had students graph the monthly average level of CO₂ from 1990 through 1995, then consider the changes.  What they saw was that while the CO₂ levels went up and down every year (plants draw CO₂ from the air during the growing season), every year the averages increased.

When I first used the activity in 2005, I decided to use more recent data - and had to create a new graph form.  The original form only went up to 370 parts per million.  By 2004, levels were already reaching 379 ppm.

In the pre-industrial world, the average CO₂ level was around 280 ppm.  In 200 years of burning fossil fuels, from 1800 to 2005, we brought it up to 380.  It took only 8 more years to bring it up another 20 ppm.  The average rate of increase is just under 2 ppm/year.

My last year of teaching, the level reached 400 ppm for the first time (based on studies of glacial ice and ocean sediments) for one day during the month of April 2013.

This year the average CO₂ levels for the entire month of April were 401.33 ppm.  

This is not good news.