by Les Grady, Environmental Engineer, retired
Driven mainly by carbon dioxide (CO2) emissions, Earth’s climate is changing.
- Evidence from diverse sources confirms climate change.
- Atmospheric temperature reconstructions show that current warming is unprecedented within the span of human civilization.
- Oceans are warming.
- Glaciers are melting.
- Sea level is rising.
- The Arctic ice cap is shrinking, the ice is thinning, and its nature is changing.
- Although East Antarctic ice is increasing, West Antarctic ice is decreasing much faster.
- Weather is getting more extreme.
- Ecosystems are changing more rapidly.
- Evidence for the role of CO2 as the main cause of climate change is very strong.
- Earth’s temperature is stabilized and regulated by the greenhouse effect.
- The major greenhouse gases (GHGs) are CO2 and water vapor.
- Water vapor is responsible for 50% of the greenhouse effect, but its life in the atmosphere is short because it condenses as rain and snow. CO2 is directly responsible for 20% of the greenhouse effect, but its indirect effect is much larger. Because it does not condense, it stays in the atmosphere for a very long time, thereby influencing the water vapor content and regulating Earth’s temperature. It is Earth’s thermostat.
- The level of CO2 in the atmosphere is increasing because of the burning of fossil fuels (coal, oil, and natural gas).
- Satellites show a reduction in outgoing (i.e., cooling) radiation leaving Earth at the wave-lengths associated with CO2 and other GHGs.
- Land-based sensors show an increase in incoming (i.e., warming) radiation from CO2 and other GHGs consistent with their increased concentration in the atmosphere.
We must release less each year to stabilize Earth’s climate.