February 04, 1989
Last week, scientists from the United States Commerce Department’s National Oceanic and Atmospheric Administration said that a study of temperature readings for the contiguous 48 states over the last century showed there had been no significant change in average temperature over that period. Dr. (Phil) Jones said in a telephone interview today that his own results for the 48 states agreed with those findings.
Right after the year 2000, NASA and NOAA dramatically altered US climate history, making the past much colder and the present much warmer. The animation below shows how NASA cooled 1934 and warmed 1998, to make 1998 the hottest year in US history instead of 1934. This alteration turned a long term cooling trend since 1930 into a warming trend.
But NASA and NOAA have a little problem. The EPA still shows that heatwaves during the 1930s were by far the worst in US temperature record.
Today the Earth's axial tilt is about 23.5 degrees, which largely accounts for our seasons. Because of the periodic variations of this angle the severity of the Earth's seasons changes. With less axial tilt the Sun's solar radiation is more evenly distributed between winter and summer. However, less tilt also increases the difference in radiation receipts between the equatorial and polar regions.
One hypothesis for Earth's reaction to a smaller degree of axial tilt is that it would promote the growth of ice sheets. This response would be due to a warmer winter, in which warmer air would be able to hold more moisture, and subsequently produce a greater amount of snowfall. In addition, summer temperatures would be cooler, resulting in less melting of the winter's accumulation. At present, axial tilt is in the middle of its range.