Over the past week I have seen news articles all over the place that 2011 was the 9th hottest year ever recorded. Not only that, but 9 of the 10 hottest years are since the year 2000. The NASA news release (GISS) is the main source for this statement, but it has been everywhere. Press releases like this are really good examples of irrelevant arguments, while being misleading at the same time.
Here is the associated chart with the press release:
I have been discussing the problems with only showing the temperature anomaly recently and nothing has changed. Most of the warming that has taken place on this chart has taken place since 1980. This is convenient to me since the satellite data is available since 1979 and since there seems to be continuous revisions upwards in the station data, I am going to focus on the satellite data to discuss 2011.
I will start by showing the Earth’s temperature for the past 32 years.
I am using the same scale for the anomaly as I am for the global temperature. Each year the Earth’s temperature has it’s minimum in January and it’s maximum in July. That temperature range is from ~12 °C to ~16 °C for a yearly temperature swing of ~4 °C. This puts the temperature of the Earth for 2011 at 14.01 °C which is 0.15 °C above the 13.86 °C yearly average. That 0.15 °C is an entire 4% of the annual temperature variation.
Of course according to the satellite data, 2011 was the 4th coldest of the past 14 years, which means that there are 10 years that were warmer in the past 14 years. Right away that makes the 9th hottest year claim look a little weak, but details like that aside, I would like to put some greater context to the current warmth of the Earth right now.
I will switch to the GRIP (Greenland Ice Core Project). Using that I will gladly concede that the past 100 years is the hottest period of the past 1,000 years.
This is using a 15 point average to smooth out the data. Even with this I will gladly concede that the past 100 years is the warmest of the past 1,000.
So the Earth is in the warmest decade of the warmest century of the past 1,000 years. I consider that to be essentially correct, but nor am I concerned with that fact. The reason for this is simple, the past 1,000 years happens to have been the coldest period of the past 8,000 years. So we are in the warmest part of the past 1,000 years, which is the coldest overall period of the past 8,000 years.
Greenland has been experiencing warmer climate for most of the past 8,000 years. In fact, the peak temperature that we are experiencing now is closer to the average 1,000 year period from only a few thousand years ago. Mostly the ice core shows that for the most part, the Earth is experiencing more cold climate now, than it has in a very long time.
The warmists really dislike the climate from the past 10,000 years because the Earth was warmer, but the CO2 was significantly lower than it has been recently. My only comment is that we should enjoy the warm weather now before the climate swings cold again.