Climate Change: Causes, Impacts, and Solutions
Climate Change Is Already Here
United Nations Response to Global Change
The United Nations, established in 1988, created the Intergovernmental Panel on Climate Change (IPCC). The IPCC predicts an average global temperature increase between 1.5°C and 5.8°C for the current century.
Evidence of Climate Change:
- Retreating glaciers and ice sheets (the saltwater ice layer covering polar oceans). Summer ice cover in the Arctic Ocean has decreased by 14%, and its thickness has reduced by 40%.
- Rising sea levels at a rate of 1 to 2mm per year due to melting continental ice and thermal expansion of ocean water.
- Increase in global mean temperature.
- More frequent extreme weather events like droughts, floods, heatwaves, and cyclones.
- Shifts in the behavior and distribution of many living organisms, including changes in seasonal rhythms, bird migration patterns, plant flowering seasons, and species distribution.
Factors Influencing Earth’s Temperature
The average surface temperature of a planet depends on:
- Distance from the sun, which determines solar radiation received.
- Presence and characteristics of an atmosphere.
The Composition of Earth’s Atmosphere
Clean, dry air comprises mainly nitrogen (78%) and oxygen (21%). Argon is the most abundant gas in the remaining 1%, while carbon dioxide represents only 0.036%. However, air is never completely dry and clean; it contains water vapor and aerosol particles, both naturally occurring and from human activities.
The Natural Greenhouse Effect
Without an atmosphere, Earth’s temperature would be -18°C. However, the natural greenhouse effect raises it to 15°C. Greenhouse gases allow solar radiation to pass through but trap heat, increasing the air temperature around us.
Greenhouse Gases
The most important greenhouse gases in the atmosphere are:
- Water vapor: The primary contributor to the natural greenhouse effect.
- Carbon dioxide: The second most important greenhouse gas.
- Methane: Emitted during ruminant digestion, from landfills, and swamps.
How the Greenhouse Effect Works
Solar radiation reaching Earth is dealt with in three ways:
- 30% is reflected by the atmosphere or Earth’s surface back into space (albedo).
- 19% is absorbed by clouds and other atmospheric components.
- 51% is absorbed by Earth’s surface, increasing its temperature. Greenhouse gases absorb infrared radiation emitted from the surface, heating the air and hindering heat loss to space.
Past Climates and Sea Level Change
Climate change affects the water cycle, including ocean evaporation, cloud formation, precipitation, and water runoff.
Thermal Expansion of Water
During warm periods, sea levels rise due to melting ice and the thermal expansion of warmer ocean water.
Causes of Climate Change
External or Astronomical Causes
- Changes in solar activity (sunspots).
- Changes in Earth’s orbit, which gradually shifts from nearly circular to more elliptical.
- Meteorite impacts, which can eject dust into the atmosphere, blocking sunlight and potentially causing cooling.
Internal Causes
- Changes in albedo (Earth’s reflectivity).
- Changes in atmospheric composition, particularly increases in CO2 from volcanic activity, burning fossil fuels, and other human activities.
- Changes in ocean currents, which distribute heat around the globe. The thermohaline circulation, driven by temperature and salinity differences, connects all oceans and acts as a heat conveyor belt. Disruptions to this circulation can have significant climate impacts.
The Alarming Increase in Greenhouse Gas Emissions
Carbon dioxide and methane (CH4) are the primary greenhouse gases increasing due to human activities. The main sources are:
- Burning fossil fuels (oil, gas, and coal) for energy, transportation, industry, agriculture, and residential use.
- Deforestation.
- Certain agricultural practices, particularly livestock farming (cattle, sheep, and pigs), which release methane.
Other greenhouse gases include ozone, nitrous oxide, and chlorofluorocarbons. While water vapor is the most potent greenhouse gas, its atmospheric concentration is primarily driven by natural processes. Human activities have caused a significant increase in carbon dioxide, the main driver of global warming over the past century.
Projecting Future Climate Change
Scientists use complex climate models to make projections about future climate change. These models are simplified representations of the climate system that incorporate key variables influencing climate. By adjusting these variables, scientists can simulate different scenarios and predict potential outcomes.
Climate Model Predictions
- Global average temperature will continue to increase, potentially by 1.4°C to 6°C by the end of the 21st century.
- Sea levels will rise, threatening coastal areas with flooding.
- Extreme weather events will become more frequent and severe.
- Environmental impacts will include biodiversity loss, shifts in species distribution and seasonal cycles, and ecosystem changes.
- Health impacts will include the spread of tropical diseases like malaria to new areas.
Addressing Climate Change
General Measures
- The Kyoto Protocol, which came into force in 2005, aims to reduce greenhouse gas emissions. The European Union has implemented measures such as:
- Promoting renewable energy sources (wind, solar, biomass, geothermal, tidal).
- Improving energy efficiency in transportation, appliances, and buildings.
- Investing in research and development of efficient and renewable energy technologies and carbon capture and storage.
- Protecting and enhancing natural carbon sinks (forests, oceans).
- Investigating and developing artificial carbon sinks.
- Implementing carbon emissions trading schemes.
Personal Actions
- Reduce, reuse, and recycle.
- Choose products with minimal packaging.
- Use reusable bags.
- Walk, bike, or use public transportation.
- Turn off lights and electronics when not in use.
- Lower heating and cooling usage.
By taking action to reduce our carbon footprint, we can mitigate the impacts of climate change and create a more sustainable future.