What is Climate Change?
Climate Change is a phenomenon that manifests itself in an increase of the planet’s average temperature (IPCC 2001). In the past, climate changes came from natural causes happening in our atmosphere; however, the climate change we are experiencing today, according to the United Nations Framework Convention on Climate Change (UNFCC), “is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.” (Article 1 of the UNFCC, 1992).
According to theory, the main cause of global warming is an increase of the greenhouse effect due to a rising accumulation of greenhouse gases (GHG) in the atmosphere. This natural atmospheric phenomenon happens when part of the energy radiated by the Earth (caused by warming of the planet through solar radiation) is captured and maintained by the greenhouse gases in the atmosphere.
This phenomenon has been responsible of maintaining an average temperature on Earth of 15°C, making life possible on the planet. Without these gases, average temperatures would probably lay around -18°C.
Among the main GHG in the atmosphere are water vapor (H2O), Carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and ozone (O3). Furthermore, there are a series of GHG produced by humans, such as the fluorocarbons and other substances which contain chlorine and bromide.
The Kyoto Protocol regulates the following GHG:
- Carbon dioxide (CO 2 )
- Methane (CH 4 )
- Nitrous Oxide (N 2 O)
- Perfluorocarbons (CF 4 ) y (C 2 F 6 ),
- Hydrofluorocarbons (commercial names: HFC-23, HFCS-134a, HFC-152a)
- Sulfur hexafluoride (SF 6).
Carbon dioxide is the most dominant of the greenhouse gases and it is generated mainly through the burning of fossil fuels (oil, carbon, natural gas and/or its byproducts). When the industrial revolution started over 200 hundred years ago, there existed around 280 parts per million (ppm) of this gas in the atmosphere. Current carbon dioxide concentration levels in the atmosphere today are around 350 ppm, showing an increase of 31% (IPCC 2001).
The developed countries are the main greenhouse gas producers, contributing with 55% of total global emissions. Mexico is Latin America’s number one GHG producer, with 2% of the total global emissions (INE 2001).
This increase in the quantity of greenhouse gases has resulted in a temperature rise of 0.6 °C which first appeared between 1910 and 1945; and between 1976 and 2000 (IPCC, 2001). The 90’s decade has been the warmest so far in the last millennium. It’s important to highlight that, according to the Intergovernmental Panel of Experts on Climate Change (IPCC), temperature could increase between 1.4 to 5.8°C by 2100.
Among the main evidence on climate change, besides an average superficial temperature rise, are the following:
- Decrease in the ice extension and polar ice cap on the earth’s surface. Satellite data shows that it is highly probable that there has been a 10 % reduction of the polar ice cap in the last 50 years (IPCC, 2001). On the other hand, there has also been a general recession of mountain glaciers in non-polar regions in the XX century (United Nations Framework Convention on Climate Change, Evidence on Climate Change. UNFCC)
- More intense rains and storms; longer draughts.
- Sea level rise in the whole world as well as ocean temperature rise. Scientific data shows that the medium sea level in the World has risen between 0.1 and 0.2 meters during the twentieth century (IPCC, 2001)
- Change in behavioral patterns in some animal and vegetable species. Scientists have observed induced changes in at least 420 physical processes and communities or biological species. (United Nations Framework Convention on Climate Change, Evidence on Climate Change. UNFCC)
The potential global impacts of climate change are the following:
- More extreme weather and climate events.
- Variations in the frequency of draughts and flooding.
- Sea level rise and coastal flooding caused by glacier and polar ice cap melting.
- Increase in environmental pollution and slowing down of the ozone layer’s recovery.
- Perturbation of terrestrial and marine ecosystem productivity, with possible loss of species and genetic variability.
The issue of global warming first gained importance for the International Community in the early 1970’s but it wasn’t until the 1980’s that the World Meteorological Organization and the United Nations Environmental Program are established. These organizations started to obtain scientific information on the accumulation of greenhouse gases and, it was then, that the international group on climate change is created to conduct studies on global warming, the so called Intergovernmental Panel on Climate Change (IPCC).
The United Nations Framework Convention on Climate Change was established in 1992, when 155 countries decided to try to find a solution to the problem. Later, in 1997, the countries in the Framework Convention approved the Kyoto Protocol, which promotes the reduction of polluting emissions on the part of industrialized countries by at least 5% beneath emission levels present in 1990. The Protocol entered into force on the 16th of February 2005.
Source: National Ecology Institute