Snow disappears when the temperature rises above 0 °C. This means that the snow surface gives an indication of the temperature. Furthermore, it is much easier to measure than the average temperature itself.
In the graph we see the snow-covered land area of the Northern Hemisphere since 1990.
While the CO2
concentration of the atmosphere increased by about 17% in that period -from 350 to 410 parts per million- the snow surface grew by an average of 16 thousand square kilometers per year, exactly the opposite of what was to be expected from the greenhouse gas hypothesis.
This is an indication that the greenhouse effect of CO2
is already saturated, as scientists from NASA already proved in the 1970s. CO2
is a greenhouse gas, but the addition of more CO2
to the atmosphere does not result in a significant increase in temperature.