Getting students to "think critically" has been a serious effort by educators for quite some time.  Of course time after time we've seen that in practice the critical thinking desired critically questions traditional and conservative positions.  But, if critical thinking is honestly what instructors are striving for, why not expand student thinking by challenging students to apply the technique in new, practical ways?

As a life-long atmospheric and environmental scientist and long-time college-science educator, I am constantly bombarded with material from a variety of sources, including many environmental groups.  Take, for instance, what can be labeled "sales" literature that I recently received from the Environmental Defense Fund.  The mailing contained a small double-sided poster that was titled "EXTREME WEATHER: THE CONSEQUENCE OF CLIMATE CHANGE" on the one side and "TACKLING CLIMATE CHANGE" on the other side.  I will focus only on the "extreme weather" side here as an example for effective pedagogy.

What if a teacher were to display the Extreme Weather poster in the classroom and ask students to carefully consider its contents?  The poster contains 6 text boxes, each describing a consequence of climate change:  Wildfires, Extreme Heat, Storms, Droughts, Flooding, and Swelling Oceans.  Take the contents of the Storms box, for instance.  It claims:

"Scientists have warned that climate change could bring stronger, more destructive storms.  Superstorm Sandy --  the largest tropical storm on record -- brought those predictions crashing down on the Eastern U.S. on October 29, 2012.  Responsible for at least 147 fatalities, 8.5 million people without electricity and $50 billion in damages, Superstorm Sandy's reign of terror extended inland to the shores of Lake Michigan and northward to Nova Scotia, Canada." [Emphasis in original.]

Each sentence can be evaluated literarily and scientifically.

As literature, students could be challenged to examine the style, flow, and tone of the message.  The highlighted first sentence could be assessed for its real substance:  Who are these "scientists" who have such a dire warning?  How many are we talking about, 2, 10, every scientist?  Is the statement too nebulous to even have serious meaning, regardless of the one example of Sandy that follows?   Furthermore, phrases like "crashing down" and "reign of terror" could be parsed for their effect on eliciting deep emotions and inciting readers to "doing something to save the planet."

From the science perspective, how is "stronger" and "more destructive" actually determined, including considering measurement techniques, availability of historic records, increased population and property development, and the like?  Further, what is meant by "largest tropical storm on record"?  In reality, how extensive and extreme was the storm's "reign of terror"?  In Pittsburgh, for example, the storm's "fury" was relatively light with some high winds and precipitation.  Sandy did become a Hurricane, a category 3 over Cuba, but only a category 1 (the lowest level) off the east coast of the U.S.  Does the fact of this low designation give some scope to the storm's overall intensity?

In addition, at the bottom of the poster we see the claim: "Global Warming: More Daily Record Highs in U.S. Than Record Lows."  Starting (conveniently) with the 1950s and then jumping to 2009 through 2012, pie charts display proof of this claim.  Here students can be encouraged to put statistical skills into play.  How does the selection of data and time periods affect results and conclusions?  Is the fact that the contiguous U.S. is less than two percent of the earth's surface important to consider?  And, more generally, how are statistics used to enlighten or darken reality? 

These are but a few suggestions for use in critical thinking in the classroom.  The danger in this poster-checking exercise, from a "progressive" educator's point-of-view, is that students who critically evaluate eco-activist pulp may end up not buying what the environmentalists are selling.  And that kind of thinking truly is critical.

(Note that excellent resources for teachers and students to access to effectively counter some of the "facts" of the Extreme Weather poster can be found at www.ICECAP.us and www.drroyspencer.com and, in particular, this presentation by Dr. John Christy of the University of Alabama in Huntsville: www.globalwarming.org/2013/05/31/john-christy-climate-change-overview-in-six-slides/.)

Anthony J. Sadar is a Certified Consulting Meteorologist and supporter of the Cornwall Alliance.  His new book is In Global Warming We Trust: A Heretic's Guide to Climate Science (Telescope Books, 2012).