The critical human contribution to the ghg effect and global warming

FACT: In the last 150 yrs, atmospheric CO2 concentrations have increased by more than 35%, from 280ppm to more than 380 ppm. -- Steven Schneider, Climate change science and policy, 2010.

FACT: Current concentrations of CO2 are about 27% higher than the highest values detected in the 650,000 Antarctic ice records -- 2003/5 Science Review: a synthesis of new research developments, Climate Report, Environment Canada

FACT: CO2 constitutes just 0.039% of the atmosphere. In terms of its presence in the atmosphere it is just a trace gas. However, the overwhelming majority of textbooks on atmospheric physics and climate science describe it as a major greenhouse gas.

Why?

Tyler Volk, CO2 rising: "There may not be much CO2 in the atmosphere but its effects on the climate are powerful. Infrared rays, which earth uses to cool itself to space, are exactly what CO2 is good at absorbing and re-radiating...

What gives the CO2 molecule its ability to absorb and (as a consequence of physics) re-radiate radiation in infrared wavelengths that are important to the atmos and the climate is its number of atoms: three. “More than two” is the crucial concept here, because the other important infrared capturing gases in the atmosphere also have 3 or more atoms in their molecules. When a gas has 3 or more atoms, it has modes of vibration inherent in its shape that can resonate with the frequencies of climate-affecting infrared waves. The matching enables the greenhouse gas molecules to intercept those waves and absorb their energy. Single atoms and two atom molecules do not have those particular resonant modes… ditto H20, methane, nitrous oxide, (N2O) and ozone (O3).

It is CO2 that is the environmental driver of Earth’s climate because the open bodies of available water (oceans) allow water vapor to adjust as an effect of the primary heating caused by CO2. The amount of water vapor, which will increase in response to the increasing concentrations of CO2 is therefore considered a climatic feedback to the primary greenhouse effect of CO2.

Infrared waves are crucial for understanding the greenhouse effect, because earth establishes its average planetary temperature by reaching a balance between solar energy absorbed and the infrared radiation sent into space...

The greenhouse effect from CO2 and H2O feedback keeps earth’s surface about 60F - about 33C warmer than it would be otherwise...

CO2 is not a particle that falls out or an ion that rains out in amounts substantial enough to cleanse the atmosphere after a few storms. It is a chemically very inert gas. Its molecules travel in the air until pulled into the ocean or into land plants.

Each ppm = 2.13 billion tons of carbon. Therefore if today’s CO2 concentration is 385ppm, our atmosphere now has about 820 billion tons of carbon circulating as CO2.

Humans put 225 billion tons of carbon into the atmosphere and the amount of carbon increased by 130 billion tons.

...Changes in CO2 over the Phanerozoic correlate rather well with changes in paleoclimate. Times of minimal CO2 coincide with the two most widespread and long lasting glaciations of the Phanerozoic, that during the Permo-Carboniferous and that of the past 30 million years. .. also periods of unusual warmth at high latitudes such as occurred during much of the Mesozoic correlate with periods of elevated CO2. Together these observations give support to the greenhouse gas theory of climate change on a Phanerozoic time scale." (Royer et al 2004)