Environment Counts | Evidence for anthropogenic global warming
Author: Geoff Zeiss – Published At: 2012-01-30 08:31 – (733 Reads)
10 indicators of a human fingerprint on climate change
- Humans are currently emitting around 30 billion tonnes of CO2 into the atmosphere every year.
- When we measure the type of carbon accumulating in the atmosphere, we observe more of the type of carbon that comes from fossil fuels.
- This is corroborated by measurements of oxygen in the atmosphere. Oxygen levels are falling in line with the amount of carbon dioxide rising, just as you’d expect from fossil fuel burning which takes oxygen out of the air to create carbon dioxide.
- Further independent evidence that humans are raising CO2 levels comes from measurements of carbon found in coral records going back several centuries. These find a recent sharp rise in the type of carbon that comes from fossil fuels.
- Satellites measure less heat escaping out to space, at the particular wavelengths at which CO2 absorbs heat, thus finding “direct experimental evidence for a significant increase in the Earth’s greenhouse effect”.
- If less heat is escaping to space, it going back to the Earth’s surface. Surface measurements confirm this, observing more downward infrared radiation. A closer look at the downward radiation finds more heat returning at CO2 wavelengths, leading to the conclusion that “this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming.”
- It is observed that the planet is warming faster at night than during the day, as would be expected if an increased greenhouse effect is causing global warming..
- Another distinctive pattern of greenhouse warming is cooling in the stratosphere (upper atmosphere).
- It has been observed that with the troposphere (lower atmosphere) warming and the upper atmosphere (the stratosphere) cooling, the boundary between the troposphere and stratosphere (tropopause) is rising, as is expected as a consequence of greenhouse warming.
- Satellite observations have shown that even higher the atmosphere, the ionosphere is cooling and contracting, as is expected in response to greenhouse warming.