Radiative forcing reflects the relationship between the energy balance of the Earth and forced changes (either anthropogenic or natural). Radiative forcing varies the flux changes above the atmosphere and global mean surface temperature, which in turn responds accordingly. For instance, flux changes trigger climatic changes to counteract the effect. Climate sensitivity is the assumed relationship between sustainable radiative forcing and equilibrium mean surface temperature. Radiative forcing does not accurately indicate temperature changes, but rapid adjustments such as aerosol in the troposphere level interfere with flux changes, which in turn yield a climatic change (Myhre, et al.664).
The increased population has resulted in innovations, technology advancement, and increased demand for basic needs. Manual work has been replaced with technological machines that have saved time and enhanced labor productivity. The demographic structure’s diverse requirements and the desire to satisfy their needs have resulted in the automation and production of efficient products. Some of these products are chemically enriched with carbon, nitrogen, and sulfur compounds, among others. The generation of energy through means such as nuclear and fossils has increased energy intensity in the earth system that has affected the climactic structure.
Water vapor is considered a feedback agent because it is caused by emission but instead is controlled by atmospheric temperature. Anthropogenic activities such as irrigation, burning of fossil fuels, and cooling of power plants increase the concentration of water vapor in the atmosphere. Although water vapor is a greenhouse gas, it can condense and precipitate as rain making it less harmful than CO2. The flux changes in the atmosphere caused by natural evaporation are more prominent than that caused by human activities. The maximum concentration of water vapor is controlled by air temperature, which implies a greenhouse effect results due to water vapor. The change caused by water vapor is regarded as climate feedback but not necessarily a radiative forcing. In the absence of CO2 and other gases, the temperature of the atmosphere would decrease and eventually freeze the Earth (Myhre, et al.666). Therefore, other atmospheric gases are necessary even though they might bear adverse effects on the environment.
The industrialization has increased CH4 emissions that react with OH ions in the troposphere to form a compound that dissociates the ozone layer resulting in climatic sensitivity to solar radiation, cloud cover, and humidity (Myhre, et al.674). GHGS radiative forcing agents such as chlorine, bromine, and fluorine compounds deplete the ozone layer. The Montreal Protocol amendments decreased the emission of ozone-depleting substances since the implementation of the change. OH, ions oxidize some GHGS substitutes such as perfluorocarbons and hydrofluorocarbons in the troposphere. Aerosol radiation is categorized as primary and secondary emission. Primary aerosols are less destructive and include dust, mist, salts, and fog, while secondary aerosols involve particles of chemical components such as sulfur dioxide, nitric oxide, and ammonia. Aerosol particles undergo processes such as condensation, evaporation of gaseous substances, and coagulation resulting in a physical and chemical change that affects radiation and clouds (Myhre, et al.675). Aerosols particles also absorb solar radiations or scatter radiation in spatial patterns of temperature changes. Black carbon-containing aerosols increase the absorption of ice, which results in climatic changes in the observed black ice (Myhre, et al.685).
CO2 is the leading radiative forcing agent. CO2 affects the distribution of vegetation, clouds, lapse rates, and cause global warming. However, the increased anthropogenic CO2 emission from the combustion of fossil fuels is reduced by the ocean. The ocean salts react with CO2 to form carbonic acids and, eventually, acidic salts that settle at the bottom. The CO2 ocean sink reduces the level of CO2 in the atmosphere (Myhre, et al.718). The change in density of the ocean due to the absorbed CO2 results in conventional currents that stir up winds in the sea as the CO2 water sinks, and the underlying water rises. The ocean thermal inertia has reduced global warming threats and maintained equilibrium temperatures. Although the ocean absorbs most of the CO2, some percentage remains in the oceans causing high temperatures on the sea. The warm heat causes high humidity on the ocean surface, which in turn fuels up hurricanes. CO2 is the main radiative forcing threat that the future will face. CO, an intermediate form of CO2, reduces the concentration of hydroxyl ions and has long term effects of destroying the ozone layer.
The land use by humans has also resulted in land surface albedo and influenced the surface temperature. Human activities reduce the impact of radiation on the Earth’s surface. Human activities have also changed the surface roughness, river runoffs, hydrological cycle, and directly generated heat, which have contributed to temperature changes. Deforestation has also led to decreased water vapor concentration and exposed the surface to radiation. Surface albedo refers to the ratio of the Earth the solar radiation strikes. Afforestation and agricultural activities lower albedo while deforestation increases the surface exposure to radiation. The human land use directly causes climatic changes and varies temperature across the Earth surface (Myhre, et al.686)
Myhre, Gunnar, et al. Anthropogenic and Natural Radiative Forcing.