Penn State NASA

Summary of Temperature Reconstructions


Summary of Temperature Reconstructions

We should pause and make a point or two about these temperature reconstructions because they are very important to our understanding of how Earth's climate has been changing.

  1. The temperature reconstructions from multiple proxies (see the Borehole Temperatures page) compare well with the instrumental record — this gives us a basis for thinking that the reconstructions are reliable. They are also in good agreement with the temperature reconstructed from borehole data — this gives us even more confidence in the multi-proxy reconstruction.
  2. What we see is a very dramatic warming that begins around 1900 — the blade of the "Hockey Stick" — that is far larger in magnitude and far more abrupt than any climate change we see in the reconstructed climate history.
  3. The recent warming does not appear to be part of a cycle — if it were part of a cycle, then we should expect to see a similar abrupt large cooling that preceded the warming, but nothing of the sort appears in the record.
  4. The oceans have been warming slower than the land and are absorbing the majority of the excess heat as a result of greenhouse gas emission.

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