Think humans aren't changing the Earth? Think again

The lead developer of an exhibit on our Changing Earth debunks some misconceptions about how our planet is evolving -- and how we've affected it.
Written by Christina Hernandez Sherwood, Contributing Writer

A new exhibit at The Franklin Institute in Philadelphia is exploring how mankind's response to the changing Earth will impact our future on this planet. Changing Earth, which opened Saturday, lets visitors calculate their carbon footprint, study ways to reduce carbon emissions, try to construct a building that will withstand an "earthquake" at the shake table and more.

To bring the exhibit to life, I asked the museum to debunk some misconceptions about the way the Earth is changing. Here's what Rita Mukherjee-Hoffstadt, the exhibit's lead developer and assistant director of traveling exhibits and special programs, had to say:

Human life can't change the Earth: "We are not the only type of life that has changed this planet. The first time it happened was 3.5 billion years ago when a type of bacteria began to produce oxygen as a byproduct of photosynthesis. They released all this oxygen into the atmosphere and poisoned all the other forms of bacteria living on Earth. If these simple bacteria could change the Earth forever, so can we."

The Earth needs to be saved: "Planet Earth will endure no matter what we do. It has lasted over 4 billion years in various states. At times it has been completely covered in active volcanoes, and in others frozen from pole to pole. What is more in question is our ability to live on this amazing planet. Right now the Earth's climate is ideally suited for humans. We wouldn't have always been able to live in the Earth's past climates. Will we be able to live on a future Earth radically different from the one we know today?"

Last winter's harsh weather proves the Earth is cooling: "Global warming needs to be studied by looking at global data. We can't just look at one location over a few years to determine if and how climate change is occurring. Scientists need to analyze large amounts of global temperature data. This works in the converse too: Having a few hot summers in a row is not, by itself, a sign of global warming."

Global warming is caused by the ozone hole: "The ozone hole is not the reason for global warming. Both of these environmental problems do have a common cause -- human activities that release gases into and change the atmosphere. Global warming is caused primarily from putting too much carbon into the atmosphere when coal, gas, and oil are burned to generate electricity or to run our cars. Ozone depletion occurs when chlorofluorocarbons (CFCs) -- formerly found in aerosol spray cans and refrigerants -- are released into the atmosphere. These gases, through several chemical reactions, cause the ozone molecules to break down. Once CFCs were banned and more carefully regulated, the size of the Earth's ozone hole was reduced."

Earthquakes happen more today than in the past: "Earthquakes of magnitude 7.0 or greater have remained fairly constant. There are two reasons for this misconception. First, there are many more earthquake monitoring stations today then there were in the past, so we are able to locate more earthquakes. And second, because of the recent increase in global communication, the public now learns more instantly and dramatically about earthquakes than in previous times."

City dwellers have a higher footprint than their suburban counterparts: "Even though the suburbs have a lot of grass, they aren't greener. Per household, urbanites have a smaller carbon footprint than those who live in the suburbs. People in urban environments tend to walk and take public transportation more frequently, and live in smaller attached homes."

Image: Earth's western hemisphere / NASA

This post was originally published on Smartplanet.com

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