Hurricane!

From a list of Global Warming Myths, number one.

Myth #1: Scientists Agree the Earth Is Warming. While ground-level temperature measurements suggest the earth has warmed between 0.3 and 0.6 degrees Celsius since 1850, global satellite data, the most reliable of climate measure- ments, show no evidence of warming during the past 18 years. [See Figure I.] Even if the earth's temperature has increased slightly, the increase is well within the natural range of known temperature variation over the last 15,000 years. Indeed, the earth experienced greater warming between the 10th and 15th centuries - a time when vineyards thrived in England and Vikings colonized Greenland and built settlements in Canada.

This is a case where one data set showing no temperature rise does not prove temperatures are not going up. Plenty of data sets do show 1) that temperatures have risen over the past 20 years and 2) that temperatures are well correlated to carbon dioxide levels.