Over the past month or two it has not been uncommon to hear skeptics of global climate change mutter that the overlong winter/spring proves that it’s all a hoax. They argue that because the weather has been colder than they are used to for a few weeks in a relatively small area, the Earth cannot possibly be warming.

Pay no mind to the fact that 2012 was the warmest year since U.S. average temperature records started in 1895, at 3.2 degrees above normal. Or that atmospheric carbon dioxide levels reached their highest concentration on record, as levels are expected to pass from the current global average of 395 parts per million to 400 within a few years.

Evidence is not terribly convincing, though, as most people — myself included — cannot actually picture the difference between 395 and 400 parts per million. Anecdotal evidence like the fact that a day last week was really cold seems to hold more sway.

I’m always for a healthy dose of skepticism; it’s important to question authority indiscriminately. But valuing informal observations over the opinions and research of women and men who have devoted their lives to studying these phenomena does not count as real skepticism. It only counts as ignorance.

The most common refrain one encounters from these people is the idea that small, contained bursts of cold disprove the notion that the Earth is getting hotter. This comes from a misunderstanding of the concept of average global temperature, which takes into account things like localized heat waves and cold snaps.

Minnesota’s April and May provide a perfect example. Local news and public radio stations were crowded with stories of golf courses prevented from opening because of late-season snows and people frustrated by the persistent cold. But global temperatures from April were 0.18 degrees above average and 0.13 degrees above average from May.

But those numbers aren’t very big. They’re little enough for people with no background in climatology to disregard. And that’s the problem. This skepticism is an excuse to ignore an issue that affects us all.