How much has the Earth warmed?

Although individual records vary, the overall trend is very clear.

Although individual records vary, the overall trend is very clear.

By Claire

I’d like to think that it’s a well known fact that the Earth as whole has warmed over the last century. I know that there is some debate as to the particulars of where is warming and by how much, but when we take a step back, it’s clear that the Earth is hotter now than it was at the beginning of the last century (it’s even hotter than it was at the beginning of THIS century).

A few weeks ago, the latest global temperature data from 2012 was released by NASA GISS, the UK Met Office, NOAA and the Japanese Meteorological Agency. All four institutions tally temperature data from stations around the world and make independent judgments about whether the year was warm or cool compared to other years. Although you can see that the individual records vary in their exact measurements of global temperatures, there is great agreement between records when you look at the overall trend. The last decade or so represents the warmest years on record (since 1880 on this plot), with the 10 warmest years on record all occurring since 1998.

“One more year of numbers isn’t in itself significant,” GISS climatologist Gavin Schmidt said. “What matters is this decade is warmer than the last decade, and that decade was warmer than the decade before. The planet is warming. The reason it’s warming is because we are pumping increasing amounts of carbon dioxide into the atmosphere.”

Screen shot from the "Your Warming World" tool by New Scientist

Screen shot from the “Your Warming World” tool by New Scientist

If you want to see just how much temperatures have increased in individual locations, check out this brilliant tool, put together by New Scientist.

The “Your Warming World” interactive tool allows you to click on any location, and see the raw temperature data from that site. What you notice once you start clicking around is that the amount of warming varies hugely between sites, with the polar areas recording much more warming than locations near the equator. You’ll also notice that the records from places like Antarctica are relatively short compared to places that have seen human settlement for much longer periods of time.

Even though the individual records vary, again, you see a common trend between most records. The Earth is warming.

One response to “How much has the Earth warmed?

  1. I was looking at some of the temperature records from a few places. In Canberra, temperatures remained relatively constant until about 1970. Since then, temperatures have risen about 1 degree, which is pretty close to the global average (though it fluctuates a bit more). In my home province of Manitoba, temperatures have risen about 3 degrees in the past 100 years, and 2012 was the warmest year on record. It would be interesting if they also had charts of the actual station data, rather than just the modelled values.

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