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   Author  Topic: Estimation problems  (Read 358 times)
Benny
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Estimation problems  
« on: Jul 25th, 2009, 7:25pm »
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Can you estimate how many new trees do we need to plant each year to offset our CO2 emissions?
 
List of countries by carbon dioxide emissions per capita
 
Wood is composed mainly of a substance called lignin cellulose. A fully grown pine tree contains up to 1/2 a ton of the stuff. About 44% of the weight of each molecule of cellulose is made of carbon, so the tree contains about a quarter of a ton of carbon. That quarter ton will have come from just under 1 ton of atmospheric CO2 while the tree was growing.
 
It's a bit tricky since our emissions are changing all the time
 
1990 .. 1991 .. 1992 .. 1993 .. 1994 .. 1995 .. 1996 .. 1997 .. 1998 .. 1999 .. 2000 .. 2001 .. 2002 ..   
18.9 .. 18.7 .. 18.4 .. 19.3 .. 19.5 .. 19.3 .. 19.4 .. 20.2 .. 19.8 .. 19.9 .. 20.4 .. 20.1 .. 20.0 .. 19.8 ..  
 
2003 .. 2004    
19.8 ... 20.4
 
Say the average American is responsible for 20 tons of CO2 emissions each year.
 
In that case, you'll need to grow 20 new trees each year to be carbon neutral.
 
This would mean  
 
U.S. Population: 303,824,640 (July 2008 est.)
 
303,824,640 x 20 = 6,076,492,800 trees
 
planting and maintaining 6,076,492,800 new trees every year.
 
The spacing between mature pines in a forest is 4 yo 5 yards, so each tree occupies a ground area of 20 square yards. In round figures, the area of land needed for new forest will be over 120 billion square yards.
 
That's around 38,740 square miles ... that's almost the size of the State of Indiana.
 
see U.S. States : Area and Ranking
 
Your thoughts, please. Could anyone come up with a better estimate?
« Last Edit: Jul 25th, 2009, 7:38pm by Benny » IP Logged

If we want to understand our world — or how to change it — we must first understand the rational choices that shape it.
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