On Warming in Colder, Drier Climates

One of the reasons some people believe increased carbon dioxide caused the warming from the late 1970s through 1998, is because most of the warming occurred in cooler and drier areas of the world. These areas included parts of Canada, Northern Europe, and Siberia, as well as some of the northern parts of China and the United States. Increased amounts of gases which absorb infrared radiation might do this. One such gas is CO2, but anything causing an increase in water vapor in these drier areas would be as likely an explanation.

There may be another explanation. As noted in an earlier post or comment, about 11% of the incoming radiation from the sun is in the form of ultraviolet radiation, about 44% is visible light, and about 45% is infrared radiation. It has been noted that increased solar activity accounts for some of the increase in temperature from the 1970s until 1998. We know that Mars, Jupiter, Neptune, Pluto, and Neptune's moon Triton have all similarly warmed. Some scientists claim that this does not account for all of the warming on earth in this period, though a similar increase did in the early warming period of 1910 through the 1930s.

During a period of increased radiation from the sun, the warming due to the increased visible light portion of the sun's spectrum is treated by the models, but the effects on the incoming infrared radiation from the sun are cavalierly ignored. In the colder climate areas in the northern latitudes, the atmosphere is drier and there is less water vapor in the atmosphere to absorb incoming solar infrared radiation at higher altitudes. More of this infrared radiation will then reach the ground and lower altitudes and warm them. This would cause a given increase in solar radiation to have a greater warming effect in the drier and colder areas of the earth. Hence, warming occurs more in these areas than others, entirely independent of the wee little concentrations of CO2 in the atmosphere.

In other words, there is no reason to believe that the observed added warmth in the late 1970s to 1998 period found in these cold, dry areas is evidence that increased atmospheric carbon dioxide was the primary reason for temperature increases. This may well make sense also in light of the fact that if CO2 were responsible for that warming, then the highest temperatures should be found in the atmosphere at altitudes of about 10 Km. Atmospheric altitude temperature measurements have been unable to find a maximum in the temperature profile at that altitude or anywhere near it. This has long been a serious reason to believe that the models predicting the warming based on increased CO2 are simply wrong.

Another serious problem with the idea that CO2 has caused the warming is that before 1760 the CO2 concentrations were extremely low at less than 280 parts per million. The rise in CO2 from that time has been appreciable since 1850 and rapid since 1950. Yet the temperature increases in northern, dry latitudes did not start until at least the mid-1970s. This is important since additions to CO2 are supposed to have more effect when the concentration is low and less and less added effect as the concentration increases. The carbon dioxide warming hypothesis does not work well and is not required as an explanation. Natural solar activity appears to be the primary reason for the warming of the 1970s to 1998, with a complex coupling with ocean currents.

It is critical to take the incoming solar infrared radiation into account as well as the visible light when calculating the temperature in various regions due to solar radiation.