Steps

A reader recently asked about a post on WUWT which, to everyone’s shocking surprise, claims to contradict man-made global warming. It claims that temperature records (at individual stations) follow step changes rather than linear increase, so the theory of anthropogenic global warming (AGW) is wrong.

Trend and Cycle Together

Many climate signals show both trend and cycle (usually an annual cycle) together. A typical example is the concentration of carbon dioxide (CO₂) in the atmosphere. If you look at the data (say, from the Mauna Loa atmospheric obsevatory) both the trend and the cycle are obvious.

Open Thread

The last thread is intended only to enable anyone to express an opinion about the probability of disastrous climate change under business-as-usual.

But it’s natural that folks want to discuss related issues, and even argue with each other about their stated estimates.

So — here’s an open thread. Please use the “What is epsilon?” thread ONLY to state your estimate, use this one to discuss at length. Thanks.

What is epsilon?

I recently posted about the unfortunate failure to examine data properly which contributed to the disastrous loss of life with space shuttle mission 51-L (the Challenger disaster). One of the members of the commission which investigated the disaster was physicist Richard Feynman.

Data and Code for Foster & Rahmstorf 2011

This post is only to provide access to the data and the code (all computations were done using R) used in Foster & Rahmstorf 2011 (blogged about here).

Oh Pleeze

WUWT has another post by Jim Goodridge. It makes one question whether that blog has any standards for truth or accuracy.

Johnny’s Growth

Suppose, just for argument’s sake, that when your son Johnny turned 2 years old you decided to monitor his growth. His birthday is Jan. 1, so on the first of every month you measure his height — you even mount a tape measure permanently on the wall so you can measure him in the same location each time. You dutifully record the number for each measurement. Your wife thinks this is “cute” so she decides to take a picture every time you do, and puts them in a photo album labelled “Our Growing Child.” Since she’s a professional photographer, she uses her amazing Nikon super-high-res digital camera. All her friends think it’s super-cute.

The Real Global Warming Signal

Many different factors affect Global temperature. Fake “skeptics” like to claim that mainstream climate scientists ignore everything but greenhouse gases like CO₂, when in fact it’s mainstream climate scientists who identified those other influences. Natural factors cause temperature fluctuations which make the man-made global warming signal less clear, fluctuations which are often exploited by fake skeptics to suggest that global warming has paused, or slowed down, or isn’t happening at all. A new paper by Foster & Rahmstorf accounts for some of those other factors, and by removing their influence from the temperature record makes the progress of global warming much more clear.

Best Defense

There’s a saying in American Football (and perhaps other sports too) that “The best defense is a good offense.”

1400+ Years of Arctic Ice

We have precise data for Arctic sea ice extent from satellite observations over about the last 30+ years, and a pretty good estimate for the last century or more from ship and aircraft observations. The data show clearly that Arctic sea ice has declined dramatically over the last few decades, a decline the like of which has certainly not been seen for over 100 years prior to that. In addition, a recent survey of available proxy information — not a reconstruction, but a thorough review of the evidence — tells us that the modern decline in Arctic sea ice is “unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.”

Now there’s even more evidence of the shocking state of the Arctic sea ice. New research reports an actual reconstruction of the extent of Arctic sea ice over the last 1,450 years (Kinnard et al. 2011, Nature, 479, 509-512, doi:10.1038/nature10581).