Rather than address Allison Bolgiano on whether I'm a "pathological denier" (of climate change), I'll reply to the more reasonable letter by Elizabeth Fones (CO2 is known to be a factor in warming the atmosphere, March 11).
Tyndall did discover the "greenhouse effect" theory but he and others didn't have all the facts. CO2 and other "greenhouse gases" do absorb solar IR (thankfully, or we'd be an icy snowball).
Water vapor does most of the work, however (95 percent of greenhouse gas compared to CO2's 3 percent including man's barely significant fraction of total CO2). Glaciers do advance or retreat due to temperature and abatement. Kilimanjaro's ice loss, however, was the poster boy for global warming until it was realized that the summit is always below freezing and its ice ablated because lack of snowfall due to deforestation around it. Glaciers must be replenished by snow or they recede.
Greenland, Antarctica and glacial ice core (oxygen isotope) data, some going back hundreds of thousands of years show climatic events such as the Dalton (solar) Minimum, the 1880-1915 cool period, the 1915-1945 warm period, the 1945-1977 cool period, and many other temperature cycles that fluctuated, for example, between warm and cool periods at least 22 times between 1480 and 1950. None of the warming periods were caused by increased CO2.
They all preceded periods of rising CO2 levels with only one warming period in the past 500 years happening simultaneously with rising CO2 (1977-1998). CO2 obviously not the cause of warming. The Greenland ice core isotope records match climatic fluctuations recorded in alpine glacier advances and retreats.
During the 1880-1915 cool period, alpine glaciers advanced almost to their Little Ice Age (1300-1915) maximums, then retreated strongly during the 1915-1945 warm period with no significant change in atmospheric CO2. They readvanced from 1945-1977 in a cool period during which CO2 soared dramatically - just the opposite of what should have happened if CO2 caused global warming.
Some of this data is from Don Easterbook's "Evidence-Based Climate Science, Data opposing CO2 emissions as the primary source of global warming," authored by leading international climate scientists, each with over 25 years of experience in the field. It has 400-pages of excellent data, graphs and charts with comprehensive citations, references and bibliography.
Climate variability is complex, but regarding "warmist" politicians and the IPCC: "The urge to save humanity is almost always a false front for the urge to rule it." (Mencken).