Climate change refers to long-term changes in average weather conditions, including temperature and precipitation, observed over periods exceeding thirty years.
Natural Greenhouse Effect
Solar radiation enters the Earth's atmosphere.
Greenhouse gases (CO₂, CH₄, N₂O) trap some of the outgoing heat.
Heat is re-radiated back to the surface, warming the planet.
Some heat escapes into space.
Human-Enhanced Greenhouse Effect
Increased concentrations of greenhouse gases (CO₂, CH₄, N₂O) due to human activities.
Less heat escapes into space, more heat is re-emitted.
Leads to a greater amount of re-radiated heat, amplifying the warming effect.
Source & Composition of Greenhouse Gases
CO₂: 79.7%
CH₄: 11.1%
N₂O: 6.1%
HFCs, PFCs, SF₆, and NF₃: 3.1%
Other: 12%
Non-Energy Use of Fuels: 5%
Industrial: 2%
Electricity: 16%
Transportation: 30%
Commercial: 35%
Global CO₂ Emissions by Country (2017)
Global total: 36.2 billion tonnes
Asia: 19 billion tonnes (53% of global emissions)
China: 9.8 billion tonnes (27% of global emissions)
India: 2.5 billion tonnes (6.8%)
North America: 6.5 billion tonnes (18% of global emissions)
USA: 5.3 billion tonnes (15% of global emissions)
Europe: 6.1 billion tonnes (17% of global emissions)
EU-28: 3.5 billion tonnes (9.8% of global emissions)
Russia: 1.7 billion tonnes (4.7%)
Other significant emitters:
Japan: 1.2 billion tonnes (3.3%)
Iran: 672 million tonnes (1.9%)
Saudi Arabia: 635 million tonnes (1.8%)
South Korea: 616 million tonnes (1.7%)
Canada: 573 million tonnes (1.6%)
Mexico: 490 million tonnes (1.4%)
Indonesia: 489 million tonnes (1.4%)
South Africa: 456 million tonnes (1.3%)
Australia: 414 million tonnes (1.1%)
Ukraine: 212 million tonnes (0.6%)
Africa: 1.3 billion tonnes (3.7% of global emissions)
South America: 1.1 billion tonnes (3.2% of global emissions)
Oceania: 0.5 billion tonnes (1.3% of global emissions)
International Aviation & Shipping: 1.15 billion tonnes (3.2%)
Cumulative CO₂ Emissions (1900-1999)
Total: 933,686 million metric tonnes
Top 12 Countries: 223,944 million metric tonnes (24%)
United States: 83,251
Russia: 68,313
Germany: 65,167
UK: 34,294
Japan: 26,529
France: 21,914
Ukraine: 21,366
Canada: 19,047
Poland: 18,678
India: 15,349
Italy: 7,928.5
181 Other Countries: 709,742 (76%)
Per Capita Energy Consumption (2001)
Measured in kilograms of oil equivalent (KGOE)
Top Consumers:
North America: 7,928.5 KGOE
Europe: 3,621.3 KGOE
Middle East/North Africa: 1,487.1 KGOE
ASIA: 1,265.4 KGOE
CARRIBEAN: 1,088.8 KGOE
Central America/South America: 890.1KGOE
Atmospheric CO₂ at Mauna Loa Observatory
Measured in parts per million (ppm)
Increasing trend since 1960
2025 projection: 427 ppm
Temperature & Carbon Dioxide
Correlation between temperature and CO₂ levels
Global temperature anomalies adjusted to early industrial baseline (1881-1910)
2025 CO₂ projection: 427 ppm
Climate Change on Different Time Scales
1,000,000 years: Plate tectonics
100,000 years: Orbital variations and glacial periods
100-10 years: Events like the Little Ice Age and Medieval Warm Period
10-5 years: El Niño – La Niña cycles
Other short-term cycles due to ocean circulation
Climate is always changing.
Global Temperature and CO₂
Historical data on CO₂ concentration, sea level, and global temperature
Data from Eemian period, Last Ice Age, and Holocene
Rising Global Temperatures
April Global Temperature Departure: 1940-2024
Hottest Year on Record
2024 was the hottest year on record.
Record-warm seasons and daily global average temperatures.