Reading the National Climate Assessment: Riveting

I've been slowly working my way through the draft of the National Climate Assessment Report.

Parts have been riveting.

Chapter 2 on "Our Changing Climate" is an incredible compendium and synthesis.

The key messages read like a list of our worst fears. Temperatures up 1.5°F since 1895. More heat waves, floods, droughts, and hurricanes. Less ice. Sea levels up 8 inches since 1880.

One of the most quotable lines:

"The sum total of this evidence tells an unambiguous story: the planet is warming."

The section on heat waves stood out most for the jump in certainty that has been made:


"The 2011 and 2012 events set records for highest monthly average temperatures, exceeding in some cases records set in the 1930s, including the highest monthly temperature on record (July 2012, breaking the July 1936 record); for the spring and summer months, 2012 had the largest area of record-setting monthly average temperatures, including both hot daytime maximum temperatures and warm nighttime minimum temperatures (Karl et al. 2012). Corresponding with this increase in extreme heat, the number of cold waves has reached the lowest levels on record.

"In the past 3 to 4 decades in the U.S. the ratio of record daily high temperatures to record daily low temperatures has steadily increased (also see Meehl et al. 2009).


"Research has found that the human contribution to climate change approximately doubled the
probability of the record heat in Texas in the summer of 2011 (Hoerling et al. 2012a)."

Compared to even the last IPCC or the last NCA, these syntheses are much stronger.

I guess when you think about it,  what has happened to our climate in just the past 4 years is much stronger.