Global warming
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Causes of Global Warming: Greenhouse Gases and Human Activities
Global warming is primarily driven by human activities, especially the burning of fossil fuels (coal, oil, and gas) and large-scale deforestation, which release significant amounts of greenhouse gases (GHGs) into the atmosphere. The most important of these gases is carbon dioxide (CO2), but methane (CH4) and nitrous oxide (N2O) also contribute, though their concentrations are much lower than CO2. Water vapor is responsible for about two-thirds of the greenhouse effect, but CO2 is the main controlling factor—without increased CO2, global warming would not have occurred. The rise in GHGs over the past century is mainly due to fossil fuel combustion, industrial activities, agriculture, and deforestation Houghton2005Al‐Ghussain2018Mounesh2024+1 MORE.
The Greenhouse Effect and Climate Change
Greenhouse gases absorb infrared radiation emitted by the Earth's surface, effectively trapping heat and keeping the planet warmer than it would be otherwise. This process, known as the greenhouse effect, is well understood and is the fundamental cause of global warming. As GHG concentrations rise, the Earth's average surface temperature increases, leading to changes in climate patterns Houghton2005Al‐Ghussain2018Mounesh2024+1 MORE.
Observed and Projected Impacts: Temperature Rise, Extreme Weather, and Sea Level
The Earth's surface has already warmed by about 1.2°C since the preindustrial era, with recent years seeing even sharper increases. For example, global temperature jumped by more than 0.4°C in just two years, reaching +1.6°C above late 19th-century levels, partly due to reduced aerosol emissions from ships and a strong El Niño event Hansen2025Song2022. This warming accelerates the melting of glaciers and polar ice caps, raising sea levels and increasing the risk of coastal flooding. Extreme weather events—such as heatwaves, droughts, storms, and heavy rainfall—are becoming more frequent and intense, impacting agriculture, water supplies, and vulnerable communities Houghton2005Mounesh2024Hansen2022+2 MORE.
Economic and Social Consequences
Global warming has worsened global economic inequality. Poorer, hotter countries have experienced significant declines in economic output, while some cooler, wealthier countries have seen relative gains. This has led to a 25% increase in between-country economic inequality over the past half-century, with the poorest countries suffering the most from the impacts of warming .
Human Health and Survival
Rising temperatures threaten human health by disrupting the body's ability to regulate temperature, increasing the risk of heat-related illnesses and deaths. Global warming also affects food and water supplies, housing, infrastructure, and economic activities, posing severe risks to human survival, especially in vulnerable populations .
Climate Sensitivity and Future Projections
Scientific analyses suggest that doubling atmospheric CO2 could increase Earth's average surface temperature by about 3.8°C, though the exact amount depends on feedbacks within the climate system. Recent studies indicate that future warming may be greater than previously estimated, and achieving global temperature stabilization targets will require even steeper reductions in GHG emissions Al‐Ghussain2018Hansen2022Brown2017.
Mitigation and Adaptation Strategies
To limit global warming to 1.5°C above preindustrial levels, as targeted by the Paris Agreement, global GHG emissions must be halved by 2030 and reach net zero around 2050. This requires rapid transitions to renewable energy, increased energy efficiency, reforestation, sustainable agriculture, and international cooperation. Both mitigation (reducing emissions) and adaptation (preparing for inevitable impacts) are necessary. However, current national commitments are insufficient, making it likely that the 1.5°C limit will be exceeded in the coming decades Al‐Ghussain2018Mounesh2024Hansen2022+1 MORE.
The Need for Urgent and Coordinated Action
The consequences of unchecked global warming are severe, including accelerated sea level rise, more extreme weather, and potential disruptions to major ocean currents. Addressing global warming demands urgent, coordinated action at local, national, and international levels, with a focus on both reducing emissions and protecting vulnerable populations Houghton2005Mounesh2024Hansen2022+2 MORE.
Conclusion
Global warming is a critical environmental and societal challenge caused mainly by human-induced greenhouse gas emissions. Its impacts are already being felt worldwide, affecting weather, economies, health, and ecosystems. Immediate and ambitious action is essential to mitigate further warming, adapt to unavoidable changes, and ensure a sustainable future for all.
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