In the last past years, the Earth has been experiencing increasing temperatures, leading to harmful consequences on our planet and its habitants. This has been researched and analysed, concluding to name such changes as Global climate change. As explained by the US agency, the National Oceanic and Atmospheric Administration (NOAA), there are 7 indicators that would be expected to increase in a warming world, and 3 indicators would be expected to decrease.
Global Climate Change has been recognised as an increase in average global temperatures. 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.
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:
and some artificial chemicals such as chlorofluorocarbons (CFCs). 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 vapour, 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 2°F to 11.5°F by 2100, depending on the level of future greenhouse gas emissions, and the outcomes from various climate models. By 2100, global average temperature is expected to warm at least twice as much as it has during the last 100 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 IPCC Special Report on Emissions Scenarios: B1 is a low emissions scenario, A1B is a medium-high emissions scenario, and A2 is a high emissions scenario
Causes of Global Climate Change:
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 (CO2), methane (CH4), nitrous oxide (N2O) and the halocarbons (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 1750), 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. Deforestation releases CO2 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 sulphur compounds, organic compounds and black carbon (soot). Human activities such as surface mining and industrial processes have increased dust in the atmosphere.
Natural forcing’s 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 sulphate aerosol in the stratosphere.
As a result, in today’s atmosphere, the radiative forcing from human activities is much more important for current and future climate change than the estimated radioactive forcing from changes in natural processes.”
Principal components of the radiative forcing of climate change.
All these radiative forcings 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 vapour, surface albedo, aerosols and contrails. The only increase in natural forcing of any significance between 1750 and 2005 occurred in solar irradiance. Positive forcings lead to warming of climate and negative forcings lead to a cooling.
The percentage contribution to global warming over the past 50-65 years is due to human and natural causes.
Studies and analysis made have shown that humans are by far the dominant cause of recent global warming.
Most studies showed that recent natural contributions have been in the cooling direction, thereby masking part of the human contribution and in some cases causing it to exceed 100% of the total warming. The two largest human influences are greenhouse gas (GHG) and sulphur dioxide (SO2) emissions, mostly from burning coal, oil, and natural gas. The largest natural influences on the global temperature are the 11-year solar cycle, volcanic activity, and the El Nino Southern Oscillation (ENSO).
Global Warming, mainly human caused
It is found and conclude with this analysis and investigation, that most of the observed increase in globally average temperatures since the mid-20th century is due to human activities impacts. Leaving humans the main and higher impact on the Earths situation. Global warming is mainly human caused.
http://www.environment.gov.au/climate-change/climate-science/greenhouse-effect http://www.nmsea.org/Curriculum/Primer/Global_Warming/fossil_fuels_and_global_warming.htm http://www.globalissues.org/article/233/climate-change-and-global-warming-introduction#WhatisGlobalWarmingandClimateChange http://www.epa.gov/climatechange/science/future.html