The mental math references for Environmental are below. At the bottom of the page you’ll find a list of sources for each figure, with the precise data point from that source.

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General stats

World’s tallest tree

World’s longest river

World’s largest lake

Area of Antarctica

Area of Arctic ice in summer

Global fish catch

Global sea level rise per year

Global average temperature rise since 1880

Global petroleum reserves

Global natural gas reserves

Global coal reserves

Atmospheric CO2 concentration

Ozone layer thickness

Global wind speed average

Global ocean salinity

Global renewable energy investment

Cost of carbon offset

Average air quality index in U.S.

Average air quality index in China

Natural disasters annually

Global annual rainfall

Desert area globally

Coral reefs globally

Global wetlands area

400 feet

4,000 miles

140,000 square miles

5 million square miles

2 million square miles

100 million tons/year

0.1 inches

1° Celsius

350 million barrels

20 trillion cubic meters

200 billion tons

400 parts per million

300 Dobson units

10 miles per hour

35 parts per trillion

$350 billion/year

$60 per metric ton




40 inches

20 million square miles

100,000 square miles

7 million square kilometers


Global CO2 emissions

U.S. CO2 emissions

EU CO2 emissions

China CO2 emissions

40 gigatons/year

5 gigatons/year

3 gigatons/year

10 gigatons/year


Global deforestation

Amazon deforestation

25 million acres/year

3 million acres/year

Water usage

Global fresh water usage

Average U.S. water usag

4,000 cubic kilometers per year

100 gallons per person per day

Energy capacity

Global wind energy capacity

Global solar energy capacity

Global hydro energy capacity

Global nuclear energy capacity

Global geothermal energy capacity

900 gigawatts

1,000 gigawatts

1,500 gigawatts

400 gigawatts

15 gigawatts

Pollution & waste

Ocean plastic pollution

Global waste generation

U.S. waste generation

10 million tons/year

2 billion tons/year

300 million tons/year

Note: All dollar figures are in USD.


General stats

World’s tallest tree: 380.3 feet — Wikipedia

World’s longest river: 4,160 miles — Guinness World Records

World’s largest lake: 143,244 square miles — AmericanOceans.org

Area of Antarctica: 5.5 million square miles — Wikipedia

Area of Arctic ice in summer:1.8 million square miles  — NASA

Global fish catch: 106 million tons/year — Our World In Data

Global sea level rise per year: .13 inches — NASA

Global average temperature rise since 1880: 1° Celsius— Wisconsin.gov

Global petroleum reserves: 350.3 million barrels — Department of Energy

Global natural gas reserves: 17 trillion cubic meters — EIA

Global coal reserves: 227.7 billion tons — EIA

Atmospheric CO2 concentration: 421 parts per million — NOAA

Ozone layer thickness: 300 Dobson units — NASA

Global wind speed average: 7-7.4 mph — Scientific American

Global ocean salinity: 35 parts per trillion — NOAA

Global renewable energy investment: $358 billion/year — BNEF

Cost of carbon offset: $40-$80/metric ton — 8 Billion Trees

Average air quality index in U.S.: 39.9 — USAfacts.org

Average air quality index in China: 53 — AQI

Natural disasters annually: 6,800 — TheZebra.com

Global annual rainfall: 39 inches  — Britannica

Desert area globally: 18.9 million square miles — University of Texas

Coral reefs globally: 110,000 square miles — EarthDay

Global wetlands area: 6.38 million square kilometers — FHWA


Global CO2 emissions: 36.8 gigatons/year — IEA

U.S. CO2 emissions: 6.3 gigatons/year — EPA

EU CO2 emissions: 2.73 gigatons/year — Statista

China CO2 emissions: 10.4 gigatons/year — Worldometers


Global deforestation: 24.7 million acres/year — Our World In Data

Amazon deforestation: 3.2 million acres/year — Statista

Water usage

Global fresh water usage: 4,000 cubic kilometers per year — Parks and Rec Business

Average U.S. water usage: 82 gallons/person per day — EPA

Energy capacity

Global wind energy capacity: 906 gigawatts — GWEC

Global solar energy capacity: 1,185 gigawatts — Wikipedia

Global hydro energy capacity: 1,360 gigawatts — Hydropower.org

Global nuclear energy capacity: 413 gigawatts — IEA

Global geothermal energy capacity: 16.1 gigawatts — Think GeoEnergy

Pollution & waste

Ocean plastic pollution: 12 million tons/year — Eunomia

Global waste generation: billion tons/year — Statista

U.S. waste generation: 300 million tons/year — EPA