There are many ways to value the natural world.

We may argue it has intrinsic value and needs assigning no other. Its beauty suggests an inherent aesthetic value. And we rely on the natural world to live, meaning it has an immense, perhaps encompassing, practical value.

However, despite the significant value many of us place on the natural world, much of it is disappearing; habitats and species are being degraded and lost.

In recent years, scientists have therefore started to investigate the financial value of nature. They do so to inform us, and how scant conservation funds might be best spent, and to broaden the debate about how and why nature should be conserved.

It is widely acknowledged that the natural world should not just be reduced to a series of financial values, which are necessarily estimates.

However, in a world that often focuses on money, it can be a useful tool to help remind us that nature does have a value, and what might be lost if aspects of it disappear.

The BBC Earth index and Costing the Earth interactive game are based on the following sources. Where appropriate, some figures have been rounded. The figures have been researched either by BBC Earth, or by, where cited, Dr Tony Juniper in collaboration with The United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), as part of an original scoping study.

Natural resources:

Freshwater

Value: $73.48 trillion

Renewal of water supplies is dependent upon a variety of natural assets, for example, healthy soils, wetlands and forests. Without new freshwater there would soon be no economy, so the total aggregate value of the water-related services provided by Nature is presented as at equivalent to global GDP (about $73.48 trillion). Researched by Juniper/WCMC-UNEP.

Trees

Value: $16.2 trillion

The numbers presented in relation to the contribution made by trees are derived from Costanza, R. et al. (2014). Changes in the global value of ecosystem services. Global Environmental Change. The number for ‘trees’ is produced from an aggregation of figures presented in this paper in relation to different kinds of forests. Researched by Juniper/WCMC-UNEP.

Coral reefs

Value: $9.9 trillion

The numbers presented in relation to the contribution made by coral reefs are derived from Costanza, R. et al. (2014). Changes in the global value of ecosystem services. Global Environmental Change. Researched by Juniper/WCMC-UNEP.

Wild sea fish

Value: $274 billion

The value of wild sea fish is derived from The Sunken Billions, a joint study published in 2008 by the World Bank and by the Food and Agriculture Organization (FAO) of the United Nations. Researched by Juniper/WCMC-UNEP.                                    

Plankton

Value: $222 billion

The value of plankton is estimated on the basis of their role in carbon capture and is derived from Siegel, D.A. et al. (2014). Global assessment of ocean carbon export by combining satellite observations and food-web models. Global Biochemical Cycles. The six billion tonnes of carbon captured by plankton was multiplied by ‘the social cost of carbon’ as calculated by the US Government (at $37 per tonne). Researched by Juniper/WCMC-UNEP.

Bees and other pollinators

Value: $170 billion

The value of bees and other pollinators in producing food was calculated by Gallai, N. et al. (2008), Economic valuation of the vulnerability of world agriculture confronted with pollinator decline. Ecological Economics. Researched by Juniper/WCMC-UNEP.

Coastal wetlands in US

Value: $23.2 billion

The protective value of coastal wetlands in the US was calculated by Costanza, R. et al. (2008), The value of coastal wetlands for hurricane protection. Ambio.

Polar bears in Canada

Value: $6.320 billion

The economic value of polar bears was researched on behalf of the Canadian government in a study prepared by ÉcoRessources Consultants. (2011), Evidence of the socio-economic importance of polar bears for Canada. Species at Public Risk Registry.

Sharks

Value: $944 million

The economic value of sharks around the world is based on a study by Cisneros-Montemayor, A.M. (2013), Global economic value of shark ecotourism: implications for conservation. Oryx.

The Grand Canyon

Value: $711 million

The US government has measured the economic output of its various National Parks in 2014, including the Grand Canyon, accessible on a website produced by the US National Parks Service, as published on 5 October, 2015.

Yellowstone National Park

Value: $543.7 million

The US government has measured the economic output of its various National Parks in 2014, including Yellowstone, accessible on a website produced by the US National Parks Service, as published on 5 October, 2015.

Dung beetles

Value: $380 million

The economic value of dung beetles around the globe was calculated by Losey, J.E. and Vaughan, M. (2006) The economic value of ecological services provided by insects. BioScience.

Corbett Tiger Reserve India

Value: $235.2 million

Based on the Centre for Ecological Services Management (CESM), and Indian Institute of Forest Management, Bhopal study (2015) Economic value of tiger reserves; A value+ approach. An exchange rate of 0.016 US dollars to each Indian rupee was used to convert 14.7 billion rupees to US dollars.

Manta rays

Value: $140 million

Calculated by O’Malley, M.P. et al (2013) The global economic impact of manta ray watching tourism. PLoS One.

Birds in Seattle

Value: $120 million

Calculated by Clucas, B.et al (2015) How much is that birdie in my backyard? A cross-continental economic valuation of native urban songbirds. Urban Ecosystems.

Wild river eels

Value: $72 million

The global value of wild caught river eels is estimated by the Food and Agriculture Organization (FAO) of the United Nations in its 2012 annual yearbook of Fishery and Aquaculture Statistics, p 48.

Wild sturgeon

Value: $5 million

The global value of Wild sturgeon is estimated by the Food and Agriculture Organization (FAO) of the United Nations in its 2012 annual yearbook of Fishery and Aquaculture Statistics, p 48.

A beaver

Value: $120,000

Beavers, through building dams and other structures, change the environment in ways that can benefit people. One study by Buckley, M. et al. (2011) The economic value of beaver ecosystem services Escalante River Basin, Utah. ECONorthwest, Portland, Oregon, found the overall contribution of all beavers running to hundreds of millions of dollars. Researched by Juniper/WCMC-UNEP.

Acre of oyster reef

Value: $6,800

The value of the services provided by oyster reefs is calculated by Grabowski J.H. et al (2012). Economic valuation of ecosystem services provided by oyster reefs. Bioscience. The figure is converted from hectares to acres.

A sea otter

Value: $6,250

The individual and overall value relating to sea otters comes from Loomis, J. (2005). Economic benefits of expanding California’s southern sea otter population. Colorado State University. Researched by Juniper/WCMC-UNEP.

A wild salmon

Value: $81

The value of a single wild salmon is calculated by Richardson, S. and Loomis, J. (2009) The total economic value of threatened, endangered and rare species: An updated meta-analysis. Ecological Economics.

An Indian vulture

Value: $65

The value of vultures is based on their past contribution in India. Following a period of rapid decline, the work they did in clearing up the bodies of dead animals was ended, causing disease risks and generating costs for alternative means of dealing with rotting carcasses. The financial value of this was calculated by Markandya, A. et al. (2008). An appraisal of the human health and other benefits of vultures in India. Ecological Economics. Researched by Juniper/WCMC-UNEP.

A bald eagle

Value: $39

The value of a single bald eagle is calculated by Richardson, S. and Loomis, J. (2009) The total economic value of threatened, endangered and rare species: An updated meta-analysis. Ecological Economics.

A gray whale

Value: $35

The value of a single gray whale is calculated by Richardson, S. and Loomis, J. (2009) The total economic value of threatened, endangered and rare species: An updated meta-analysis. Ecological Economics.

A wild turkey

Value: $13

The value of a single wild turkey is calculated by Richardson, S. and Loomis, J. (2009) The total economic value of threatened, endangered and rare species: An updated meta-analysis. Ecological Economics.

Artificial resources:

The United States

Value: $17.42 trillion

The US is valued by its Gross Domestic Product (Purchase Power parity), (2014 est), provided by the US Central Intelligence Agency (CIA) World Factbook.

Oil

Value: $3.33 trillion

The global annual value of oil is calculated from the BP Statistical Review of World Energy (June 2015) that estimates that 92,086,000 barrels of oil were produced per day globally in 2014, sold at an average price per barrel of $98.95.

The United Kingdom

Value: $2.55 trillion

The UK is valued by its Gross Domestic Product (Purchase Power parity), (2014 est), provided by the US Central Intelligence Agency (CIA) World Factbook.

Canada

Value: $1.59 trillion

Canada is valued by its Gross Domestic Product (Purchase Power parity), (2014 est), provided by the US Central Intelligence Agency (CIA) World Factbook.

US restaurants

Value: $709.2 billion

The economic value of restaurants in the US for 2014 is calculated from a report by the US National Restaurant Association, as last updated on 10 February 2015.

Switzerland

Value: $472.8 billion

Switzerland is valued by its Gross Domestic Product (Purchase Power parity), (2014 est), provided by the US Central Intelligence Agency (CIA) World Factbook.

Cuba

Value: $128.5 billion

Cuba is valued by its Gross Domestic Product (Purchase Power parity), (2014 est), provided by the US Central Intelligence Agency (CIA) World Factbook.

Walt Disney

Value: $48.81 billion

The annual revenue of The Walt Disney Company is taken from its 2014 Annual Financial Report and Shareholder Letter, and confirmed by a subsequent report published in The New York Times.

US coal

Value: $36.67 billion

The annual value of coal mined in the US in 2013 is provided by the country’s Energy Information Administration, as released on 23 April, 2015. Revenue is calculated from a US production of 984.8 million short tons in 2013, multiplied by the average sales price of coal from US mines of $37.24 per short ton in 2013.

Cinema

Value: $36.4 billion

The global box office for all films released in each country around the world during 2014 is calculated by Motion Pictures Associates in the 2015 report Theatrical Market Statistics.

Polished diamonds

Value: $25 billion

De Beers group of companies calculated the annual value of polished diamonds (revenue) in The Diamond Insight Report (2014) p 20. The figure is expressed in terms of polished diamonds sold contained in diamond jewellery at cutting centre wholesale value.

Starbucks

Value: $16.45 billion

The annual revenue of Starbucks is taken from the company’s 2014 Annual Report, p 19.

Rough diamonds

Value: $16 billion

The annual value of rough diamonds (revenue) for 2013 is calculated within the Fourth Annual Report On The Global Diamond Industry, Diamonds: Timeless Gems in A Changing World, prepared by the Antwerp World Diamond Centre (AWDC) and Bain & Company. Figure 1.2.3, as published on 9 December, 2014.

Farmed eels

Value: $1.373 billion

The global value of farmed eels is estimated by the Food and Agriculture Organization (FAO) of the United Nations in its 2012 annual yearbook of Fishery and Aquaculture Statistics, p 48.

Farmed sturgeon

Value: $271 million

The global value of farmed sturgeon is estimated by the Food and Agriculture Organization (FAO) of the United Nations in its 2012 annual yearbook of Fishery and Aquaculture Statistics, p 48.

Cristiano Ronaldo

Value: $79.5 million

Footballer Cristiano Ronaldo’s annual earnings (revenue) are based on his 2015 ranking within the World’s Highest Paid Celebrities list, produced by Forbes.com, as published on 5 October, 2015.

Beyoncé Knowles

Value: $54.5 million

Singer Beyoncé Knowles’s annual earnings (revenue) are based on her 2015 ranking within the World’s Highest Paid Celebrities list, produced by Forbes.com, as published on 5 October, 2015.

The White House

Value: $14.6 million

The US government has measured the economic output of its various National Parks in 2014, including the US Presidential White House, accessible on a website produced by the US National Parks Service, as published on 5 October, 2015.

A US District Judge

Value: $201,100

The annual earnings of a US District Judge in 2015 are shown under the Judicial Compensation Section produced by the US Courts website, as published on 5 October, 2015.

Average US worker

Value: $47,230

The annual earnings of a US worker in 2015 are calculated by the US Department of Labor’s Bureau of Labor Statistics on its website under the sections Occupational Employment Statistics and May 2014 National Occupational Employment and Wage Estimates, as published on 5 October, 2015.

Acre of US corn

Value: $244

The revenue produced by a single acre of corn planted in the US in 2014 is published by the US Department of Agriculture Economics, Statistics and Market Information System, as of 5 October 2015. The data is found within Table 18, Row 43.

Honeybee colony in US

Value: $141

The revenue produced by a single honeybee colony in the US in 2014 is published in a report published on the 20 March, 2015 by the US National Agricultural Statistics Service (NASS) of the Agricultural Statistics Board, of the US Department of Agriculture. It is calculated from an average colony yield of 65.1 pounds per year in 2014 at 216 cents per pound.

Acre of US oats

Value: $104

The revenue produced by a single acre of oats planted in the US in 2014 is published by the US Department of Agriculture Economics, Statistics and Market Information System, as of 5 October 2015. The data is found within Table 18, Row 192.

A farmed turkey

Value: $22

The value of each turkey farmed in the US in 2014 is calculated by the US Poultry and Egg Association, under the heading Poultry Production and Value 2014 Summary, as published on 5 October 2015. The value per turkey is calculated by dividing the $5.30 billion value of turkeys produced during 2014, by the 238 million turkeys raised that year.

A farmed broiler

Value: $4

The value of each broiler chicken farmed in the US in 2014 is calculated by the US Poultry and Egg Association, under the heading Poultry Production and Value 2014 Summary, as published on 5 October 2015. The value per broiler is calculated by dividing the $32.7 billion value of broilers produced during 2014, by the 8.54 billion broilers raised that year.