The Beginner’s Guide to Climate Change
Part 2: Is the Climate Changing?
Forget the question of whether or not humas are involved in the discussion of climate change for a moment; first, we must confirm that there is definite change in the climate system before we associate it with human actions. What is happening in the world today that indicates a changing climate?
Global Temperature Rise
One of the most prevalent sources of evidence for the presence of climate change is the global temperature rise, but this evidence can be misleading. It is important to note the distinction between “weather” and “climate” as they are NOT interchangeable. Weather describes the short-term state of the atmosphere; a sudden drop in temperature or a snowstorm in April is considered weather, and therefore cannot be used to describe a climate trend. Climate consists of an extremely long-term pattern (30 years minimum). This time period allows for the fluctuations in the complex atmosphere to average themselves out; for example, you may flip a coin 3 times and it may land on heads three times in a row despite the 50% odds of rolling a tail. However, if you flip a coin 100 times over a longer time frame, you can guarantee that the number of heads and tails will be almost identical. Converting this analogy to the weather, you may get an unusually cold April one year; however, if the other 29 Aprils over the last 30 years are warmer than average, then there is a clear warming climate trend. With that being said, take a look at the current global warming trend since 1900:
The bars on the graph map out the change in temperature (°F) from the global average; as shown, there is a clear trend of anomalously warm temperatures in recent years as compared to years past.
Sea Level Rise
Sea level is also a key indicator of climate change shockwaves. This is because of two intrinsic connections between water and warmth:
- When warmed, glaciers and land-ice melt; this water is released into the water bodies of the world, raising sea level
- Water expands when warmed, and this extends down to the deepest depths of the ocean
Here is the graph for sea level rise starting from 1880:
This graph works similarly to the previously provided global temperature model; the higher the streak drawn on the graph, the higher the sea level is as compared to the starting point in 1880. The data was collected both from tidal gauges along coastal research stations and broad satellite scans of the entire ocean. Once again, it is important to note that global sea-level rise isn’t always reflected on the local scale. These measurements account a cumulative measurement over an extended timespan as opposed to individual readings viewed in the short term.
With only this much evidence provided, there is a rather clear trend that the climate is changing whether or not humans are involved. Naturally, there is much more evidence across multiple corners of science that would bloat this blog to an impossible length; for further reading, head over to the Environmental Protection Agency (EPA) website on climate change indicators. Next time, we will discuss what role humans play in climate change.