Scientific American: Dear EarthTalk: Hurricane Sandy brought more sea water onto shorelines than I’d ever witnessed before, and many communities near where I live are now being required to raise their homes up. What is the prognosis for sea level rise in the years immediately ahead?—Scott P., Fairfield, Conn. Since sea level measurements were first recorded, in 1870, global averages have risen almost eight inches. The annual rate of rise has been 0.13 inches over the past 20 years, which is close to twice the average…