Global warming, or more precisely global climate change, has become a major issue in the last few decades. Climate change in Illinois, the nation, and the world has had and will continue to have direct and indirect impacts on Illinois.
We know the climate in Illinois has changed in the past due to natural forces such as changes in the amount of solar radiation, ocean circulation, and volcanoes. Humans can impact climate on a local, regional, and global scale, through increases in greenhouse gasses, changing aerosols (small particles in the air such as dust or sulfates from coal burning), and land use changes (change from prairie to agriculture to cities). Therefore, climate change is the result of complex interactions between natural and human-induced forces and remains a challenge for understanding future climate change.
The Water Survey is dedicated to monitoring and understanding climate change in Illinois. This site provides some insights on climate change in Illinois and how it relates to the U.S. and the world. A more extensive discussion of the past climate and possible scenarios of the future climate of Illinois can be found on the Illinois Water Supply Planning web page.
Here are two great interactive resources for plotting time series of temperature and precipitation for Illinois or elsewhere
The National Climatic Data Center tracks US temperature and precipitation trends at NCEI Climate at a Glance. Here are the US trends in annual temperature and precipitation through 2015.
Calculating the Earth's temperature is very challenging. Changes in sites, exposure, instruments, procedures, and observers can introduce errors and biases into the data. Observations before 1900 were more sparse and were concentrated in the land areas of the northern hemisphere. Attempts have been made to adjust for these and other issues with the data.
While no data set is perfect, several groups applying different techniques have reached similar conclusions. Furthermore, other kinds of observations support the evidence of warming. These include the observed reduction of glaciers in every continent, reductions in snow cover, shorter ice season on many lakes and rivers, and changes in the oceans.NCEI global temperature page.
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