How is it possible to predict temperatures on Earth years into the future when my local weather forecast can’t tell me if it will be raining a month from now?
What About the Climate Is Changing?
The oceans can absorb some of this additional heat, which leads to increases in their temperatures and acidities and thus has a huge impact on aquatic life. Forests and other plant life can also help by using up carbon dioxide through photosynthesis. However, humans have reached a point where we are becoming a burden on the Earth’s natural greenhouse, making it more and more difficult for the environment to correct itself.
The effects of climate change are expected to be complicated and highly varied, but a few are known for certain: 1.) On average, the Earth will become warmer, although this will not be felt to the same degree everywhere; 2.) warmer conditions will lead to more evaporation and eventual precipitation overall (although again, this will vary in extent based on region); and 3.) warming oceans will cause sea levels to rise due to both the melting of glacial ice and to the expansion of the ocean water once it is warmed.
Climate versus Weather
So, how do we know these changes will happen? Many of them have already started. The Intergovernmental Panel on Climate Change states that “scientific evidence for warming of the climate system is unequivocal.”
Temperatures on Earth go through natural cycles, including the advance and retreat of glaciers, with the last Ice Age ending nearly 7,000 years ago. However, the large scale changes in climate that we are observing are now happening on time scales of tens of years rather than the thousands or millions of years that are more typical for geological activity. For example, global sea levels rose 17 cm (6.7 inches) in the last century but that increase nearly doubled in the last decade alone. Antarctica lost 36 cubic miles of ice all in a three year time span. All 10 of the warmest years on record have also occurred in the last 12 years—statistics that cannot be due to chance.
So how can we make long term predictions about temperatures and rain level but not get storm predictions perfectly accurate on a daily time frame? The answer is that climate and weather are very different. The Earth’s climate is a description of how the Earth’s atmosphere acts over long periods of time throughout many regions and thus relates to averages in measures like temperatures and rainfall over long time scales. Weather, on the other hand, is a more detailed description of short-term changes in the atmosphere like temperature, humidity, and wind. Climate is thus a kind of long term average of weather-related events.
For more information on the effects of climate change on our Earth, including a check of our planet's "vital stats," check out climate.nasa.gov.
Until next time, this is Sabrina Stierwalt with Everyday Einstein’s Quick and Dirty Tips for helping you make sense of science. You can become a fan of Everyday Einstein on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at firstname.lastname@example.org.
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