Climate change is an overall change in the climate, warmer or cooler, hotter or drier. These changes happen cyclically, due to general global trends, catastrophic natural events, or because of human activities.
What is the difference between climate and weather?
“If the climate is warming, why did it snow today?” This common refrain illustrates the key confusion between climate and weather. Climate is defined as the average weather conditions, including temperature, humidity, precipitation, cloudiness and wind speeds, over a number of years. In general, the climate of a region is determined as the average weather conditions over 30 years. Weather, on the other hand, is a description of current atmospheric conditions, including temperature, humidity, precipitation, cloudiness and wind speeds. More simply put, the weather is current conditions, and the climate is the average weather conditions over time.
One simple analogy is to compare the weather and climate conditions to clothing. Each day, we get dressed in clothes appropriate for the current conditions outside, or what we expect that day. But at home in our closets, we have clothing appropriate for all the different weather conditions that could happen in our area throughout the year.
Because climate is an average determined over several years, there can be a lot of day-to-day variation during that time without changing the overall average. Some days are colder or wetter than normal, but other days may be hotter or drier than normal, with the average staying the same. However, during a period of climate change, the average temperature (or other climate measurement) does not stay the same over time. As the years go on, the average may trend upward or downward.
“Global warming” is a term often associated with climate change, but they are not both referring to the same thing. Climate change may include warming or cooling.
The climate change that we are experiencing right now is not the first or only time the Earth has experienced change. There are many well-documented examples of climate change throughout the Earth’s history. One of the most famous instances is the Ice Ages. The most recent Ice Age ended approximately 10,000 years ago, and left definite signs of its presence throughout Utah. Lake Bonneville, a giant freshwater lake that once stretched across the state from Idaho all the way down to south-central Utah, was formed during the Ice Age. Giant glaciers formed in the mountains, carving sharp peaks and wide canyons throughout the Wasatch and Uinta ranges. The glacier in Little Cottonwood Canyon even reached down into Lake Bonneville, calving icebergs into the water. The Ice Ages were brought about by a cooling period that helped glaciers to extend through large portions of North America. However, at the end of the Ice ages, the climate began to change again and there was a period of warming. Glaciers did not accumulate as much snow each winter, and melted faster in the summer. Eventually, many of the glaciers were gone. Lake Bonneville, without an outlet to the sea, began to evaporate away, eventually condensing down to form the Great Salt Lake.
Climate change is measured by monitoring changes in weather patterns over time. Weather records are made each day, recording the temperature highs and lows, the humidity, precipitation, and wind speed. Climate scientists look at this data and observe shifts in the average measurements over time.
For example, the average rainfall in Fictional, Texas from 1850 to 1880 may have been 12.5 inches per year. But from 1920 to 1950 the average rainfall may have been 9.8 inches per year. This indicates a change in the climate, with the area around Fictional becoming drier. Scientists could compare temperature records from those time periods as well, and use the information to update climate records and assist in making new weather predictions.
Cause and effect are not as easy to observe in large, complicated systems as we would like them to be. Climate and weather can be affected by a number of different variables in the world so it can be difficult to point to one single cause for a change.
Volcanic eruptions can put a large volume of gases and particles into the air that may take years to fall to Earth, disrupting weather patterns. Large ocean currents such as the El Nino may fluctuate over a number of years, making the cause and effect harder to spot. A decrease in the amount of solar radiation hitting the ground due to pollution in the air can lead to cooling.
When scientists look for the causes of climate change, they look at all the possible angles and collect data on all of them. Then, looking at the data all together, they make conclusions based on what they see. If one set of data changes very significantly at the same time as we see climate change, those two things are concluded to be closely linked.
In the case of our present climate change, the most significant change that has happened in the last 100 years has been the increase of carbon dioxide in the atmosphere. It is known that carbon dioxide is a greenhouse gas and causes warming. Scientists throughout the world agree that the carbon dioxide increase is the primary cause of our current climate change.
It is likely that many natural causes are also contributing to the changes we are seeing, but carbon dioxide increases caused by people is the largest contributing factor. This may be discouraging, but it is important because it means that we also can be the solution to the problem by doing our part to reduce carbon in the atmosphere.