Climate Science

Earth by NASAClimate is defined as the weather conditions prevailing in an area over a long period of time.  While weather is the day to day fluctuations in temperature, wind and precipitation, climate is a far more stable concept operating over periods of decades.  Climate has changed substantially in the past in response to natural factors such as the strength of the sun’s energy output and the composition of the atmosphere.

The idea that human actions could alter the climate has been around for over 100 years, but it is only in the last 30 years that scientists have come to the conclusion that this human influence is actually having an effect.  Human actions including deforestation (which removes plants that draw in carbon from the atmosphere), the burning of fossil fuels (which releases more carbon into the atmosphere), and the production of soot (which increases the absorption of solar radiation by the ground) are all acting to increase global temperatures.  On top of these factors are “feedbacks” which occur when a change in one factor promotes yet more change in that factor.  For example, a melting of polar ice leads to a greater exposure of the soil and rock beneath that ice.  The ice reflects solar radiation away from the earth, but the dirt and rock absorbs that radiation, warming the earth still further and increasing the rate of ice loss.  In other words, losing ice increases the rate at which ice is lost - a “positive feedback”.

Contemporary climate science has established three strong points of consensus:

  1. Climate is changing – This has been observed clearly in the global temperature record over the past 50 years.  Climate has changed considerably over the past few hundreds of thousands of years, but it was relatively stable until the middle of the 20th Century.  The strong increase in environmental temperature coincides with a surge in atmospheric carbon dioxide and an increase in other human activities that are thought to contribute to global warming.
  2. Humans are the primary cause of climate change – No scientist will claim that humans are the only cause of current climate change.  Of course factors such as the sun play a small role, just as they always have.  However, the increases in greenhouse gases produced by human activity and the changes in land use now constitute the primary forces driving climate.  It is impossible to account for recent changes in environmental temperature without taking humans into account.
  3. Climate change is dangerous – There are areas that will benefit from climate change in the short term.  For example, some areas may see increased agricultural growing seasons or a decline in the hardship associated with low temperatures. However, for every area benefiting from longer growing seasons there will be one suffering from drought or soil erosion.  For every area benefitting from lower cold-related deaths there will be one suffering from higher heat-related deaths.  These effects, coupled with sea level rise that threatens to displace millions of people, uncertainties about water resources that threaten to bring war to entire continents, the spread of infectious diseases, species extinctions, ocean acidification, and risk of forest fires, mean that climate change represents a grave threat to human society.

CASS' Position
CASS is committed to promoting the science behind climate change.  The scientific literature strongly supports the above statements that (i) climate is changing, (ii) humans are the primary drivers, and (iii) climate change is a very real threat.  CASS seeks to correct misinformation and expose denialist arguments that muddy the waters of the debate on climate change in the public discourse.

Browse below for the latest press releases, articles, and project notes by CASS on the topic of climate science.


Climate Change Denial
