Climate change, be it in the troposphere or the upper atmosphere, is one of the most critically pressing issues in our society today. Meteorologists and climate scientists have long since demonstrated the alarming rates of warming in the lower atmosphere, but the space weather community is yet to grab the spotlight. For the first time, a large enough database of observations is readily available for extensive analysis of temperature trends in the ionosphere. Data acquired from 1978 to 2007 by the Millstone Hill incoherent scatter radar (46.2° N, 288.5° E) has been analyzed in order to provide a direct estimate of temperature trends between 250 and 550 kilometers. These long-term trends indicate significant daytime hour cooling, varying between approximately -3.5 K/Year to -8.0 K/Year depending on height and time. These measurements are accurate both for ion temperatures (Ti) and neutral temperatures (Tn) with daytime standard deviations as low as 0.8 K/Year, showing that these are very reliable results that are considerably larger than theoretical predictions based solely on increasing concentrations of greenhouse gases in the lower atmosphere.