GH

Climate Change Notes

Climate Change

Definition

  • 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.
  • Average of 41 additional days of