24 Global Warming Climate Change 2024

Definition: Global warming refers to the long-term increase in Earth's average surface temperature due to human activities, particularly the emission of greenhouse gases (GHGs).
Current Trends: The Earth's average temperature has risen by over 1.2°C since 1850, largely attributed to increased atmospheric GHG concentrations from activities like burning fossil fuels and deforestation.

Past Extinction Events: Severe global warming events have previously led to dramatic changes in biodiversity, including mass extinctions, the Paleocene-Eocene boundary event (-55 Ma) was directly related to sudden global warming and led to the rise of mammals during recovery.
Current Rate of Change: As of today, GHG concentrations are accelerated, potentially threatening ecosystems and human societies.

Mechanism: Sunlight (shortwave radiation) passes through the atmosphere and warms the Earth's surface. The surface then emits infrared radiation that greenhouse gases (like CO2, CH4, and water vapor) absorb and re-radiate, trapping heat.
Importance of GHGs: The greenhouse effect is crucial for life; without it, Earth's average temperature would be significantly lower (approximately -18°C instead of +15°C). However, excessive GHGs are leading to dangerous warming.

Carbon Dioxide (CO2)
- Current Level: Increased from 280 ppm in pre-industrial times to about 408 ppm.
- Sources: Fossil fuel combustion, deforestation, manufactured products.
Methane (CH4)
- GWP: 25 times more potent than CO2 over 100 years.
- Sources: Agriculture (especially ruminants), landfills, energy production and leaks.
Nitrous Oxide (N2O)
- GWP: 265 times that of CO2.
- Sources: Fertilizers and agricultural practices.
Chlorofluorocarbons (CFCs)
- Use: Refrigerants and aerosols; potent greenhouse gases.
Halogenated Carbons
- Impact: Contribute to warming and ozone depletion.

Anthropogenic Factors: Human activities are the primary drivers of recent climate change, leading to increased GHG emissions and degradation of ecosystems.
Global Feedback Loops: The processes initiated by human actions can result in feedback loops - e.g., as polar ice melts, less sunlight is reflected, leading to further warming.

Tipping Points Defined: A tipping point is a critical threshold where small changes can lead to significant effects on the system, potentially resulting in irreversible impacts.
Examples:
- Thawing permafrost releasing methane; deforestation in critical ecosystems like the Amazon.
Predicted Outcomes: Increased frequency of extreme weather events, sea-level rise, shifts in agriculture, loss of biodiversity, and health impacts globally.

Adaptation Strategies: Implementation of barriers, resilient agricultural practices, and sustainable urban planning to combat climate impacts.
Reduction of GHG Emissions: Transition to renewable energy, carbon pricing, and abatement technologies (CCS and energy efficiency improvements).
International Cooperation: Adherence to agreements like the Paris Accord, aiming to limit temperature rise to below 2°C. Countries must present and meet ambitious targets.

Stabilized Earth Pathway: To prevent crossing critical thresholds leading to Catastrophic climate change, humanity must actively manage its relationship with Earth's systems.
Transformational Change Needed: A shift in fundamental societal values, economic systems, technological advancements, and policies will be essential.

Adaptation: Modifying practices to cope with climate impacts.
Mitigation: Measures to reduce climate change effects primarily through emissions reductions.
Feedback Loop: Processes where the outcome of a certain situation influences the same situation in a repetitive cycle.
Global Warming Potential (GWP): A measure of how much heat a greenhouse gas traps in the atmosphere over a specified period compared to CO2.
Tipping Point: A critical threshold beyond which significant change occurs in the climate system.
Carbon Sink: Natural systems that absorb more carbon than they emit (e.g., forests, oceans).