Natural events and human activities are believed to be contributing to such temperature increasing changes. This has led to the development of what is now known as Global Warming. Global warming has been proved as the increase of Earth s average surface temperature due the effect of greenhouse gases. Greenhouse Effect: The greenhouse effect is a natural process that warms the Earth’s surface. When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
Greenhouse gases include: water pour carbon dioxide methane nitrous oxide ozone and some artificial chemicals such as chlorofluorocarbons (CIFS). The absorbed energy warms the atmosphere and the surface of the Earth. This process maintains the Earth’s temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on Earth to exist. The greenhouse effect is the rise in temperature on Earth as certain gases in the atmosphere trap energy. Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface. In turn, the earth radiates energy back into space
Some atmospheric gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse These gases are therefore known as greenhouse gases. Predicted levels of Global Climate change: Greenhouse gas concentrations in the atmosphere will continue to increase unless the billions of tons of annual emissions decrease substantially. Increased concentrations are expected to: Increase Earth’s average temperature Influence the patterns and amounts of precipitation Reduce ice and snow cover
Raise sea level Increase the acidity of the oceans These changes will impact our food supply, water resources, infrastructure, ecosystems, and even our health . Future climate change: Future temperatures are expected to change further. Climate models project the following key temperature-related changes, identified as Key Global Projections: Average global temperatures are expected to increase by OFF to 1 1 . OFF by 21 00, depending on the level of future greenhouse gas emissions, and the outcomes from various climate models.
By 21 00, global average imperative is expected to warm at least twice as much as it has during the last 1 00 years. Ground-level air temperatures are expected to continue to warm more rapidly over land than oceans Projected changes in global average temperatures under three emissions scenarios (rows) for three different time periods (columns). Changes in temperatures are relative to 1961-1990 averages. The scenarios come from the EPIC Special Report on Emissions Scenarios: Bal is a low emissions scenario, AY B is a medium-high emissions scenario, and AY is a high emissions scenario Causes of Global Climate Change:
Human: Human activities contribute to climate change by causing changes in Earth’s atmosphere in the amounts of greenhouse gases, aerosols (small particles), and cloudiness The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere Human activities result in emissions of four principal greenhouse gases: carbon dioxide (CO), methane (CHI), nitrous oxide (NON) and the halocarbon (a group of gases containing fluorine, chlorine and bromine). These gases accumulate in the atmosphere, causing concentrations to increase with time.
Significant increases in all of these gases have occurred in the industrial era Since the start of the industrial era (about 1 750), the overall effect of human activities on climate has been a warming influence The human impact on climate during this era greatly exceeds that due to known changes in natural processes, such as solar changes and volcanic eruptions. All of these increases are attributable to human activities: Carbon dioxide has increased from fossil fuel use in transportation, building heating. Climate change releases CO also released in natural processes such as the decay of plant matter.
Methane has increased as a result of human activities related to agriculture, natural gas distribution and landfills. Nitrous oxide is also emitted by human activities such as fertilizer use and fossil fuel burning. Ozone is a greenhouse gas that is continually produced and destroyed in the atmosphere by chemical reactions. Human activities have increased ozone through the release of gases such as carbon monoxide, hydrocarbons and nitrogen oxide, which chemically react to produce ozone. Fossil fuel and biomass burning have increased aerosols containing sulfur compounds, organic compounds and black carbon (soot).
Human activities such as surface mining and industrial processes have increased dust in the atmosphere. Natural: Natural forcing arise due to solar changes and explosive volcanic eruptions. Solar energy directly heats the climate system and can also affect the atmospheric abundance of some greenhouse gases, such as stratospheric ozone. Explosive volcanic eruptions can create a short-lived (2 to 3 years) negative forcing through the temporary increases that OCCUr in sulfate aerosol in the stratosphere.
As a result, in today’s atmosphere, the irradiative forcing from human activities s much more important for current and future climate change than the estimated radioactive forcing from changes in natural processes. ” Principal components of the irradiative forcing of climate change. All these irradiative forcing result from one or more factors that affect climate and are associated with human activities or natural processes. Human activities cause significant changes in long-lived gases, ozone, water vapor, surface labeled, aerosols and contrails.