Climate change has become the most important topic for discussion in recent years and the consensus is that human activity is causing the changes.
Some people still deny that the climate is changing, but their arguments are based largely on some misunderstandings. Data collected by NASA, NOAA, the National Academy of Sciences and other agencies worldwide can help clarify the issue.
Climate change deniers confuse weather — the day-to-day changes in temperature and precipitation — with climate — the long-term patterns based on 30-year averages. One asinine senator took a snowball from a blizzard to the floor of Congress to disprove climate change. Climate change cannot be determined by a single event. During the most recent Ice Age there were enough sunny days to sustain megafauna including enough vegetation to support wooly mammoths,
The Earth has indeed gone through many cycles of heating and cooling over thousands of years. The problem we are facing is not change per se, but the speed of these changes, over a few years instead of centuries. Ice age cycles are about 100,000 years long and interglacial ages are about 11,500 years. A drop of about 4 degrees Fahrenheit in mean global temperature could trigger an ice age.
Global mean temperatures have risen by 1.4 degrees since 1900, but about 1 degree of that change has occurred since 1980. The Earth has been getting warmer at a greater rate in the last 35 years than it had been for hundreds of thousands of years.
A third problem is that deniers deliberately confuse the fact that changes in mean land temperatures are driven by changes in the oceans that cover 70 percent of the Earth.
Water can absorb much more heat than copper before its temperature changes by 1 degree. Yet mean oceanic temperatures have risen by nearly 1.5 degrees since 1900 with most of that coming since 1980. As a result, the frequency and intensity of tropical storms have risen significantly.
A good indicator of warming is the loss of ice coverage. Ice cover cools the Earth by reflecting the sun's heat. Between 1978 and 1996, Arctic sea ice shrunk by 14,000 square miles a year. The Greenland ice sheet has thinned by more than 3 feet since 1993. The number of glaciers in Glacier National Park has decreased from 150 in 1850 to 50 today and those are all shrinking.
In 2012, 362 locations in the United States set record high temperatures and none set record lows. Each year since 2012 has been hotter, with 2014 the warmest since records have been kept. The 10 highest temperatures on record have occurred since 1997.
These changes are correlated with increasing levels of greenhouse gases, primarily carbon dioxide, released by burning fossil fuels. In 1959, the atmospheric carbon dioxide was 316 parts per million but rose to over 400 ppm in 2014. Over half of this increase has occurred since 1980.
Living organisms that would gradually evolve to adapt to these changes cannot keep up with the change. The oceans absorb most of the carbon dioxide, which makes them more acidic. Coral reefs are dissolving and shellfish are struggling to construct their shells.
Migrating red knots, a species of bird that has made interpolar trips for thousands of years, timed their arrival along the east coast to coincide with the spawning of horseshoe crabs whose eggs provided a fuel source to return to the northern regions. Now the birds arrive before the crabs lay their eggs and millions die on the way home.
As the Earth warms, many tropical diseases such as malaria, dengue fever and other insect-borne diseases have dramatically expanded their ranges northward.
So when a politician refuses to address this issue by saying he is not a scientist, he is telling the truth. Over 97 percent of the world's climate scientists agree that the climate is changing and it is related to human activity of burning fossil fuels that releases carbon dioxide and methane that drive the increasing temperatures.
Congressmen may not be scientists, but at least they could be sentient.
Roger Guffey of Lexington is a retired math teacher.