planted city

Thinking Globally: ‘How Much Water is on Earth’

From The US Geological Survey:

The largest sphere represents all of Earth’s water, and its diameter is about 860 miles (the distance from Salt Lake City, Utah, to Topeka, Kansas). It would have a volume of about 332,500,000 cubic miles (mi³) (1,386,000,000 cubic kilometers (km³)). The sphere includes all the water in the oceans, ice caps, lakes, and rivers, as well as groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant.

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The blue sphere over Kentucky represents the world’s liquid fresh water (groundwater, lakes, swamp water, and rivers). The volume comes to about 2,551,100 mi³ (10,633,450 km³), of which 99 percent is groundwater, much of which is not accessible to humans. The diameter of this sphere is about 169.5 miles (272.8 kilometers).

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Do you notice that “tiny” bubble over Atlanta, Georgia? That one represents fresh water in all the lakes and rivers on the planet, and most of the water people and life of earth need every day comes from these surface-water sources. The volume of this sphere is about 22,339 mi³ (93,113 km³). The diameter of this sphere is about 34.9 miles (56.2 kilometers). Yes, Lake Michigan looks way bigger than this sphere, but you have to try to imagine a bubble almost 35 miles high—whereas the average depth of Lake Michigan is less than 300 feet (91 meters).

You can read more info and the methodology used to calculate the size of our global water supply here. 

(Photo source: US Geological Survey)

Infographic: ‘A Food System Under Strain’

From the New York Times:

The United Nations recently projected that global population would hit 10 billion by the end of the century, 3 billion more than today. Coupled with the demand for diets richer in protein, the projections mean that food production may need to double by later in the century.

Unlike in the past, that demand must somehow be met on a planet where little new land is available for farming, where water supplies are tightening, where the temperature is rising, where the weather has become erratic and where the food system is already showing serious signs of instability.

“We’ve doubled the world’s food production several times before in history, and now we have to do it one more time,” said Jonathan A. Foley, a researcher at the University of Minnesota. “The last doubling is the hardest. It is possible, but it’s not going to be easy.”

(Infographic credit: New York Times)

What: ’The World at 7 Billion: Sustaining Our Future’ presented by The Earth Institute

When: Monday, October 17 at 2:50PM EST

Where:   Columbia University, Alfred Lerner Hall, Roone Arledge Auditorium, at 2920 Broadway between 114th and 115th Street, New York, NY 

             Webcast: starting at 2:50 EST

Description:

This year we reach another milestone in global population growth, 7 billion inhabitants of Earth. It has only taken us 12 years to add an additional 1 billion people to the planet. This kind of rapid population growth puts strains on environmental, political, and financial resources. The goal of this event is to highlight key issues related to rapid population growth and offer a look at current solutions.

More details, including a short film here. Twitter hashtag: #7billioncu

Finally, if this topic is interesting to you check out the recent article in the Guardian, ‘The impact of ecological limits on population growth’.

(Image credit: Earth Institute)

Climate Change in Action: Montana’s Famous Glaciers are Melting

From Al Jazeera:

In the US state of Montana, the Glacier National Park - an area sometimes called the “Crown of the Continent” - is famous for its snow-capped mountains.

But it could soon lose its glaciers due to global warming.

Scientists warn if the ice keeps melting at this rate, the park’s 25 remaining glaciers could all melt away by the year 2030.

The US Geological Survey covers the science of Montana’s melting glaciers here. CNN has previously called them, “The poster child for climate change.”