Since the subject came up …
There are certain claims (some false) about the correlation (or not) between CO2 in the atmosphere and global temperature. Several folks have pointed out that we shouldn’t really be looking at the correlation between temperature and CO2, but between temperature and CO2 forcing.
Here’s the global average temperature anomaly since 1880 (let’s use the data from NASA, shall we?).
NOAA (National Oceanic and Atmospheric Administration) has caused quite a stir with their latest report about sea level rise. The statement attracting the most attention is:
Sea level along the U.S. coastline is projected to rise, on average, 10 – 12 inches (0.25 – 0.30 meters) in the next 30 years (2020 – 2050), which will be as much as the rise measured over the last 100 years (1920 – 2020).
The one getting far less attention than it should, is:
Sea level rise will vary regionally along U.S. coasts because of changes in both land and ocean height.
Unlike most of the critics of the report (especially the loudest ones), I actually took the time to read it.
Back in 2010, the North Carolina’s Coastal Resource Commission published the North Carolina Sea Level Rise Assessment Report. Dave Burton of “NC-20” (a trade group for business interests in the coastal counties of NC) ridiculed their results, claiming that the only sensible way to forecast future sea level rise was to fit a straight line to the data from the past, and extrapolate that into the future.
Back in 2016, Florida’s Climate Science Advisory Panel (CSAP) produced a Recommended Projection of Sea Level Rise in the Tampa Bay Region. Willis Eschenbach ridiculed their results that sea level might rise faster than it has in the historical record, saying
“Finally, look at the St. Petersburg sea level dataset, or any Florida sea level dataset. None of them show any significant acceleration, despite covering the period of recent warming. Warming but no acceleration of sea level rise … oops.”
NOAA (National Oceanic and Atmospheric Administration), in their latest report, tell us that much of the U.S. may experience a foot of sea level rise by the year 2050. Anthony Watts ridicules their results, claiming instead that sea level has been rising at a steady rate for over a century and we have no reason to believe it will do otherwise.
The most interesting thing about Frederikse et al. is that not only do they publish a new sea level reconstruction based on tide gauge data, to reckon how much sea level has risen, they also attempt to reckon where that sea level rise came from.
Here’s their estimate of sea level since 1900:
Here’s the graph from NOAA of sea level at Pensacola, FL (tide gauge data)
Some might actually look at that and think “steady rise,” but the readers of this blog would probably think otherwise. Here’s my graph of the same data:
For years, the Dave Burtons and Judith Currys of this world have shown a graph (from NOAA) of sea level measured by a single tide gauge at one location, followed by proclamations of “no acceleration” and/or “sea level rise has been steady.” They choose one for which the visual impression given by the graph supports that idea, whether the numbers do or not, especially since NOAA conveniently adds a best-fit straight-line to their graphs of tide gauge sea level, and putting a straight line on the graph plants the idea of straight-line trend (i.e. constant rate of sea level rise).
If your science gives you a result you don’t like, pass a law saying the result is illegal. Problem solved.
— Stephen Colbert
Back in 2010, North Carolina’s Coastal Resource Commission released their North Carolina Sea Level Rise Assessment Report. It suggested that communities should be prepared for 1 meter (that’s over 3 feet) of sea level rise this century. They didn’t say there would be 1 meter of sea level rise … but it was a distinct possibility, so communities should be prepared.
We have measured sea level at the Battery in New York for over 150 years, from 1856 to the present, albeit with a 14-year gap from 1879 to 1893. The monthly-average sea level data are available online from NOAA (as are the data from hundreds of tide gauge stations around the world). They even provide a convenient graph:
After posting about three different reconstructions of global sea level since 1900, I happened upon another one, this time from Frederikse et al. It’s the latest, and the team of collaborators includes top researchers on this subject, some of whom were involved in previous reconstructions. What flatters me is that it agrees so well with my own reconstruction, better than it agrees other previous efforts. If the new one is the best there is (and it seems to be), then mine is impressively close.
Here’s how mine (in red) compares to that from Frederikse et al. in black: