Volume 5, Issue 2 (2024)

Najat Saliba Aoun, Professeur – Membre au Parlement Libanais

Climate Change and Greenhouse Gases

Climate change is driven by the accumulation of greenhouse gases (GHGs) in the Earth's atmosphere. These gases, primarily carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), trap heat from the sun, creating a "greenhouse effect" that warms the planet.

Industrial Activities and GHG Emissions

Over the past two centuries, industrial activities have significantly increased the concentration of GHGs in the atmosphere. The burning of fossil fuels for energy, deforestation, and industrial processes are the primary sources of these emissions. Since the Industrial Revolution, human activities have increased atmospheric CO₂ levels from about 280 parts per million (ppm) to over 410 ppm today.

Global Warming

The term "global warming" refers to the rise in Earth's average surface temperature due to the increased concentration of greenhouse gases. This warming disrupts weather patterns, causes more extreme weather events, and affects natural ecosystems. Global warming is a key driver of climate change, which encompasses a broader range of changes, including shifts in precipitation patterns, ocean currents, and increased frequency and severity of extreme weather events.

The Troposphere

The troposphere is the lowest layer of Earth's atmosphere, extending from the surface to about 10-12 kilometers (6-7.5 miles) high. This is where most weather occurs and where the majority of life-sustaining processes take place. The troposphere contains approximately 75% of the atmosphere's mass and nearly all of its water vapor and aerosols.

Impact of GHG Accumulation

The accumulation of greenhouse gases in the troposphere creates several challenges for life on Earth. Increased GHG levels lead to higher global temperatures, which in turn cause a cascade of environmental impacts:

1. Temperature Rise: Higher temperatures can lead to heatwaves, droughts, and longer growing seasons in some regions. These changes can disrupt ecosystems and agricultural productivity.
2. Water Quality: Warmer temperatures can affect water quality by promoting the growth of harmful algal blooms, reducing oxygen levels in water bodies, and altering the distribution of aquatic species. Melting glaciers and ice caps also contribute to rising sea levels, which can lead to saltwater intrusion into freshwater systems.
3. Air Quality: Increased temperatures can exacerbate air pollution problems by enhancing the formation of ground-level ozone and other pollutants. Poor air quality has significant health impacts, particularly for respiratory and cardiovascular conditions.
4. Disease Spread: Climate change influences the spread of diseases by altering the habitats and behaviors of vectors like mosquitoes and ticks. Warmer temperatures and changes in precipitation patterns can expand the range of vector-borne diseases such as malaria, dengue fever, and Lyme disease.

Lebanon's Contribution to Localized Pollution

While Lebanon is not an industrial powerhouse and does not contribute substantially to the global carbon footprint, it faces significant environmental challenges due to localized pollution. The country's heavy reliance on diesel generators for electricity, coupled with lax enforcement of emission regulations, has led to a severe degradation of air quality.

Diesel Generators and Air Pollution

In Lebanon, frequent power outages have made diesel generators a common solution for electricity supply. These generators emit a substantial amount of pollutants, including soot particles (black carbon), nitrogen dioxide (NO₂), and carbon dioxide (CO₂).

1. Soot Particles (Black Carbon): Diesel generators release fine particulate matter, commonly known as soot or black carbon. These particles can penetrate deep into the lungs, causing respiratory and cardiovascular diseases. Black carbon also has a strong warming effect on the atmosphere, contributing to the local rise in temperatures.
2. Nitrogen Dioxide (NO₂): NO₂ is a harmful pollutant that can irritate the respiratory system and reduce lung function. It also contributes to the formation of ground-level ozone, a major component of smog, which further exacerbates air quality issues.
3. Carbon Dioxide (CO₂): Although Lebanon's overall CO₂ emissions are relatively low compared to industrialized nations, the local concentration of this greenhouse gas can still contribute to the warming of the microenvironment. Increased CO₂ levels enhance the greenhouse effect, trapping more heat and raising local temperatures.

Microenvironmental Impacts

The heavy use of diesel generators and the resulting emissions create a microenvironment where temperatures are higher than they would be otherwise. This localized warming can have several adverse effects:

1. Urban Heat Islands: The concentration of emissions in urban areas can lead to the development of urban heat islands, where cities experience higher temperatures than surrounding rural areas. This can increase energy demand for cooling, create heat stress for residents, and exacerbate health problems.
2. Health Implications: The poor air quality resulting from high levels of soot and NO₂ has serious health implications for the population. Increased respiratory and cardiovascular diseases, along with a higher incidence of asthma and other chronic conditions, place a burden on the healthcare system.
3. Environmental Degradation: The combination of air pollution and higher temperatures can stress local ecosystems. Plants and animals may struggle to adapt to the changing conditions, leading to reduced biodiversity and ecosystem resilience.

Need for Regulation and Sustainable Solutions

Addressing these challenges requires effective regulatory frameworks and the enforcement of emission standards. Transitioning to cleaner energy sources, such as solar or wind power, can significantly reduce reliance on diesel generators and improve air quality. Additionally, raising public awareness and encouraging sustainable practices can help mitigate the local environmental impact and contribute to global efforts to combat climate change.

Conclusion

The accumulation of greenhouse gases due to industrial activities over the past two centuries has set in motion a series of environmental changes that challenge life on Earth. Addressing climate change requires urgent and sustained efforts to reduce GHG emissions, transition to renewable energy sources, and adapt to the changes already underway. Effective action can mitigate the most severe impacts and help ensure a more sustainable and resilient future for all. While Lebanon's global carbon footprint may be small, addressing local pollution through regulatory enforcement and sustainable energy solutions is crucial for improving public health and environmental quality.