From MSNBC today, the mainstream media seems to deliver one of these with every cold wave.
But experts say the cold snap doesn't disprove global warming at all — it's just a blip in the long-term heating trend.
Here is your chance to play "expert." Below are the most recent (up through December, 2009) satellite-derived temperatures (click for larger image). You can make up your own mind whether temperatures have warmed since 1998 or are warming now. Temperatures fell in December compared to the previous month.
What is concerning about the current trend is that we have an El Nino in the Pacific, which is known to warm the earth (the 1998 spike was caused by El Nino). Given that we've had a quiet sun and that the oceans (outside of El Nino) are running colder than average, what happens when the El Nino (likely) disappears later this year? Humanity has usually done better with warmer weather.
Here is a similar scare story about global warming -- from 1922!
(Hat Tip: Anthony Watts)
UPDATE: No sooner than I posted this than I got an email from Jan Null alerting me to the fact the El Nino has crossed the threshold into the "strong" category. This brings up an interesting point: Look at temperatures during the "strong" El Nino of 1998. Look at temperatures for the most recent months. It is much cooler now.
Given that El Nino tends to drive temperatures up, one can conjecture that temperatures would be much lower if the El Nino was gone. Mother Nature may be giving us an opportunity to learn something about which factors (sun, ocean currents, CO2, etc.) are the main drivers of climate.