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The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it. But the impact of human activities on our planet continues to grow. Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it. Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert. Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly. Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia. Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise. The effects of this on the planet are increasingly evident. Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn. The massive wildfires in and around Los Angeles have made major changes in the local landscape. Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs. Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high. These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

We often hear about how the weather is getting stranger all the time, but do most of us really think so? What kinds of weather do we really find remarkable and has that been changing?

A study led by the University of California, Davis used some very modern tools to examine the question of what people might consider to be “normal” weather. To reach their conclusions, they quantified the timeless pastime of talking about the weather by analyzing Twitter posts. They sampled over 2 billion geolocated tweets to determine what kind of events generated the most posts about the weather.

Unsurprisingly, they found that people most often tweet when temperatures are unusual for a particular place and time of year. However, if the same weather persisted year after year, it generated less comment on Twitter, indicating that people began to view it as normal in a relatively short amount of time.

The study indicates that people have short memories when it comes to what they consider normal weather. On average, most people base their idea of normal weather on what has happened in just the past two up to maybe eight years. This disconnect with the historical climate record may obscure the public’s perception of climate change.

After repeat exposures to historically-extreme temperatures, people talk less about the weather, even though particularly hot or cold weather conditions make them unhappy and grumpy. Even though we are experiencing conditions that are historically extreme, we might not consider them to be particularly unusual if we tend to forget what happened more than a few years ago. Things may be getting worse, but they apparently are just the new normal.

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Tweets tell scientists how quickly we normalize unusual weather

Photo, posted March 11, 2013, courtesy of Adedotun Ajibade via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The human footprint on Earth

The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it. But the impact of human activities on our planet continues to grow. Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Web Links

The New Normal Weather

We often hear about how the weather is getting stranger all the time, but do most of us really think so? What kinds of weather do we really find remarkable and has that been changing?

Web Links