During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well.
Glaciers: Then and Now - Classroom Activity Kit

Classroom activity kit includes Glaciers: Then and Now Activity Description, Student Worksheet, and one or more sets of laminated glacial image pairs from the National Snow and Ice Data Center.
Single set of eight laminated glacial image pairs - $14.99
Four sets of eight laminated glacial image pairs - $49.99. This set is appropriate for a class size of ~20, with each group of five students working with a set of eight image pairs.
