When it comes to hot-button issues like global warming, advocates often play fast and loose with facts. A few examples of that trend have popped up in recent weeks, with different outcomes.

The syndicated columnist George Will argued in the Washington Post this month that scientists were suffering from “eco-pessimism” and were wrongly predicting calamitous effects from climate change. As evidence, he pointed to the case of sea-ice and whether recent trends are attributable to human-induced global warming. Will referenced the University of Illinois’ Arctic Climate Research Center, claiming that this outfit reported “global sea ice levels now equal those of 1979.”

Many bloggers have followed this issue, including Carl Zimmer at The Loom, who has diligently followed the data and–apparently unlike Will or his fact-checkers–corresponded with researchers at the Illinois center. It turns out that global sea ice levels are now significantly lower than in 1979. The Washington Post has repeatedly swatted away calls to issue a correction.

Al Gore took a different approach when it was revealed he had made a mistake with data about weather-related disasters. As Andy Revkin pointed out at Dot Earth Gore has pulled a slide he used in a recent talk at a meeting from the American Association for the Advancement of Science. In that talk, Gore referred to data showing a rise in weather calamities and attributing them to humans. The data came from the Center for Research on the Epidemiology of Disasters at the Catholic University of Louvain in Brussels, but that center in its report has cautioned that it would be misleading to attribute the upward trend in “hydro-meteorological” disasters to climate change, a point Roger Pielke Jr., quickly noted at Prometheus.