Question

How do scientists measure changes in the levels of global atmospheric co2?

a. they have directly measured co2 in the atmosphere since 1758.
b. they measure co2 levels in water trapped deep in earth's crust.
c. they take ice core samples that allow measurement of co2 over hundreds of thousands of years.
d. a and
b.
e. a, b, and
c?

Answer 1

All of the above is your Answer.