What are the causes of increase in temperature of the world?

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Causes of Increase in Global Temperature

Greenhouse Gases and Anthropogenic Activities

The primary driver of the increase in global temperatures is the rise in greenhouse gases, particularly carbon dioxide, methane, and nitrous oxides, due to human activities such as burning fossil fuels, deforestation, and industrial processes . These gases trap heat in the Earth's atmosphere, creating a greenhouse effect that leads to global warming. Since the mid-19th century, human activities have significantly increased the concentration of these gases, resulting in a notable rise in average global temperatures.

Natural Variability and Volcanic Activity

Natural factors also contribute to temperature fluctuations. Variations in solar irradiance and volcanic aerosols have been identified as significant natural causes of temperature changes. Volcanic eruptions can inject large quantities of aerosols into the stratosphere, reflecting sunlight and temporarily cooling the Earth's surface . However, these natural factors alone cannot account for the sustained increase in global temperatures observed over the past century, indicating a dominant role of anthropogenic influences .

Differential Changes in Daily Temperatures

The narrowing of the diurnal temperature range (DTR), which is the difference between daily maximum and minimum temperatures, has also been linked to global warming. This phenomenon is partly due to increased cloudiness and atmospheric aerosol loading, which affect the Earth's radiation balance. The DTR has been decreasing in most parts of the world, contributing to the overall rise in mean surface temperatures.

Oceanic Heat Uptake and Energy Imbalance

The Earth's oceans play a crucial role in modulating global temperatures by absorbing excess heat. More than 90% of the heat from global warming is stored in the oceans, leading to thermal expansion and sea level rise. Changes in surface winds and oceanic currents, such as the Pacific Decadal Oscillation (PDO), also influence the distribution of heat within the ocean, affecting surface temperature trends.

Regional Variations and Aerosol Effects

Regional studies have shown that the warming effects of greenhouse gases are detectable across various land areas, including North America and Europe. However, the cooling effects of sulfate aerosols, which reflect sunlight, can partially offset this warming in some regions. In Asia, the presence of black carbon, a component of soot, has been linked to reduced aerosol cooling and enhanced warming.

Long-term Climate Change Projections

Projections indicate that if the current trend of increasing greenhouse gas emissions continues, global temperatures could rise by 0.6 to 4°C by 2050. This warming is expected to have widespread impacts, including the reduction of glaciers and ice, shifts in species distributions, and more frequent extreme weather events such as floods, droughts, and forest fires .

Conclusion

The increase in global temperatures is primarily driven by anthropogenic activities that release greenhouse gases into the atmosphere. While natural factors like volcanic activity and solar variability contribute to short-term fluctuations, the long-term trend of rising temperatures is largely due to human influence. The narrowing of the diurnal temperature range, oceanic heat uptake, and regional variations in aerosol effects further complicate the global warming scenario. Addressing this issue requires a concerted effort to reduce greenhouse gas emissions and transition to renewable energy sources.