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EDUCATION: THE CARBON QUESTION

Preliminary Carbon Investigations and Training

Investigation 2: Using the Right Tools to Study Carbon: Maps and the Biodiversity of World's Biomes

Guiding Question: How is carbon distributed around the world and how is it connected to regional environmental characteristics?

One of the fundamental ways to understand and study carbon is based on ecosystem-type or biomes. You will use what you know about biomes to make some conclusions about spatial variation in carbon storage around the world.

Each biome is characterized by a different community of plants and soils which are influenced by abiotic factors. Different plant and soil types store different amounts of carbon. Human activities can influence the health and function of ecosystems, as well as the amount of carbon they stores. Such activities as agriculture, forest plantations, and urban and suburban development influence the type and amount of vegetation and soil. In turn, these factors determine the amount of carbon in an area. In managing our land resources humans can change the global carbon budget.

Some specific questions you should answer in this investigation are:

  1. How does our understanding of biomes and the different plants and soils that make them up, help us to understand how carbon is stored in different places around the world?
  2. How can biome maps, which show patterns of biodiversity around the world, help us to look at how carbon storage varies from place to place?

Your investigation tasks are to use the data provided below in Figure 1: The World Biome Map and in Table 1: Carbon Storage in the World's Biomes, to develop your own scientific findings about the global characteristics of carbon storage on land.

Using the data in Figure 3 and Table 1, address the science objectives of your study to find:

  1. Which biome covers the greatest area of the Earth's surface?
  2. Quantify how much carbon is stored in all of Earth's vegetation combined. Do the same calculation for soil. Globally, is more carbon stored in soils or vegetation?
  3. Which forest biome has the greatest proportion of carbon in the trees compared with that biome's soil?
  4. In which component (vegetation or soils) do grasslands store most of their carbon?
  5. Table 1 below tallies the total carbon stored in the vegetation and soils of 9 of the world's biomes. However the numbers listed there are total carbon storage values for each biome. How can we compare the relative carbon storage of two different biomes if one biome covers 3,500,000 km2 and another one covers 22,500,000 km2? Fill in the final two columns of the chart by calculating how much carbon is stored in vegetation per km2 in each biome. Do the same for soils.
  6. Which biome has the most carbon stored in vegetation per km2?
  7. What happens to the carbon stored in soils?
  8. Which two biomes in the Table 1 are not labeled on the Biome Map? Why do you think each one was left off of the map? Do you think they should be included in a world map of biomes? Why or why not?
  9. How much carbon is stored in the vegetation and the soil of tropical forest per square kilometer? Do the same calculations for cropland. Based on these calculations, what can you conclude about the carbon storage ability of forests versus croplands?
  10. What are ways in which tropical forests may be threatened today and in the future?
  11. Although it is difficult to measure deforestation rates around the globe, researchers at the Food and Agriculture Organization have concluded that rainforest was being lost at a rate of 53,000 square miles (137,269 km2) per year during the 1980s. Use that rate per year and the area and carbon data from Table 1 to predict the number of years it will take to lose half of the carbon that is currently stored in tropical forest vegetation.
  12. Deforestation data from the NASA Earth Observatory's feature on Tropical Deforestation: The Rate of Deforestation
  13. If half of the tropical rainforest is converted to agriculture, how much stored carbon (vegetation and soils) will be lost?
  14. Based on your understanding that each biome is a type of system with related biotic and abiotic factors, suggest 2 possible future scenarios for how the world.s tropical forest ecosystem may change in the future. Be sure to quantify your findings and support your scenarios with evidence of why you think they are possible.
  15. An individual carbon atom can remained stored in plant tissue or in the soil on a timescale of days to decades. The carbon atom will then be transported to one of the Earth's other reservoirs (atmosphere or ocean). As already mentioned, carbon is removed from the atmosphere through photosynthesis. It is returned by respiration or by the decay of organic materials or through combustion (fire). How do different rates of organic matter decay affect the long-term storage of carbon on land? How would understanding fire patterns in each biome help us understand the longevity of terrestrial carbon storage in each biome?
  16. In addition to supporting various types of life, including human life, how does biodiversity (variety in nature) help to regulate carbon storage and thus, produce a habitable climate to support life on Earth?

Figure 3
Figure 3: World Biomes Map. Image from worldbiomes.com


Biome Area (106km2) Total Carbon stored in Vegetation (Gt) Total Carbon stored in Soils (Gt) Carbon stored in Vegetation per km2 (Gt) Carbon stored in Soils per km2 (Gt)
Rainforest 17.6 212 216    
Temperate Forest 10.4 59 100    
Boreal Forest 13.7 88 471    
Grassland 22.5 66 264    
Chaparral 12.5 9 295    
Desert 45.5 8 191    
Tundra 9.5 6 121    
Wetlands 3.5 15 225    
Croplands 16.0 3 128    

Table 1: Carbon storage in the World's Biomes

One Gigatonne (Gt) = one billion tonnes. Modified from Watson et al., IPCC Special Report on Land Use, Land-Use Change and Forestry and based on Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen (WBGU), 1998: Die Anrechnung biologischer Quellen und Senken im Kyoto-Protokoll: Fortschritt oder Rückschlag für den globalen Umweltschutz. Sondergutachten 1998, Bremerhaven, Germany, 76 pp.

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