Droughts, floods, disease, migration, food shortages, risks of conflict, etc.: the second part of the fifth report of the Intergovernmental Group of experts on the United Nations on climate change (IPCC), published Monday, March 31, are already observable impacts of climate change. According to this text from the IPCC, result of a huge work of reading and compilation of twelve thousand scientific publications, climate change has had in recent decades ‘on all continents and in the oceans’ impact, primarily on natural systems. In many areas, the change in precipitation patterns and the melting of snow and glaciers modified hydraulic systems, “affecting water in quantity and quality.
The climate change has also had a more ‘negative impact ‘ than positive on food production (wheat and maize). The range, the number of individuals or migratory practices of many marine and terrestrial species are changed. So many findings that push the IPCC to darken even further its perspectives on the effects of global warming in the 21st century. “The likelihood of serious, extensive and irreversible impacts increases with the intensification of global warming”, warns the IPCC.
IPCC speaks of risk “high to very high” If average increase in temperatures of 4 ° C compared to pre-industrial (‘substantial extinction of species’, ‘significant risks for food security’), but refers to “considerable” from a 1 to 2 ° C warming risks. An increase of approximately 2 ° C compared to pre-industrial could result in a loss of 0.2 to 2% of the global annual revenues. The countries of the South more exposed to food insecurity. ‘All aspects of food safety are potentially affected,’ says the text, including access to resources and the stability of prices, in a context where global demand will increase. By the end of the 21st century, the IPCC predicts an overall oceans resources decrease, regardless of the level of warming. On Earth, the production of wheat, corn and rice should be assigned with a local increase of the thermometer of 2 ° C compared to the end of the 20th century, “Although some regions could benefit”.
Map of fishing areas should be redesigned with more marine species in the middle and high latitudes, and down around the tropics with ‘high rates of extinction at the local level. The situation will worsen, according to the IPCC, after 2050, exposing more countries in Africa and South America.
Less water available for agriculture
The IPCC feared a reduction in “significant” surface water and groundwater in most dry subtropical regions, with impacts on the quality of these waters. The text evokes risks of shortages in Africa, in Asia and in the South of the Australia, and talks about a potentially increased pressure on the resources available in Europe (particularly in the South of the continent, which should be submitted to a higher heat) and in North America.
Climate change will “slow economic growth, make it harder to the reduction of poverty (…)”. and  create new pockets”, especially in the cities, according to the report.
More conflicts and insecurity
The IPCC is counting on an increase of population displacements, and “risk of violent conflict” with “a worsening of the classical factors of poverty and economic shocks. Risks of conflict between States with rivalries over scarce resources such as water, fish stocks, or new opportunities generated by the melting of ice around.
Flooding and erosion
According to the IPCC, these phenomena will increasingly affect the coastal and low-lying areas due to the increase of the sea level. “The population and exposed property will significantly increase” because of population growth and urbanization. On the other hand, the proportion of the population affected by major flooding will increase. IPCC cites among urban areas of Europe, Asia and Latin America, where the massive urbanisation increases the risk of flooding.
The IPCC expects an increase in health problems in many regions, especially developing countries (increased waves of intense heat, poor nutrition or contamination of water or food-related diseases). The text referred notably to Africa a change in the geography of diseases due to changes in the regime of rainfall and temperatures.
Increased risks of extinction
These risks relate to “a large part” the marine, and terrestrial species of many “will be unable to move quickly enough to find more suitable climates” after climate change. Critical marine ecosystems, such as poles and coral reefs, are especially vulnerable with acidification of the oceans. An increase in the mortality of trees could occur in many regions.
“The risks associated with climate change can be reduced by limiting its speed and scope,” recalls the IPCC, which advocates “to accommodate” warming expected. Among the measures recommended in the report: the installation of warning systems, shelters against cyclones and floods; the protection of mangroves to spare ribs; improve water storage and irrigation techniques; the creation of new agricultural practices; improved vaccination programs; the creation of protected areas and the identification of vulnerable groups; the diversification of the economy.
Global warming (global warming in English) is the global land and ocean temperature increase. The greenhouse gas greenhouse issued, due in large part to human activity, are the major contributors to the increase in temperature. These gases are released by the use of hydrocarbons (gas, oil, coal), but also methane (used for refrigeration and air conditioning). This phenomenon is also accentuated by the massive deforestation.
Consequences of global warming
Among the consequences of global warming, the increase in the level of the oceans and the increase of extreme weather events (floods, typhoons, cyclones…) are the most striking. The loss of animal species and the reduction of the agricultural yield of certain lands are also possible.
Responses to global warming
Become eco responsible is within the reach of all. Many progress has been made with respect to energy awareness. Promote public transit, better isolate his or her home or prefer LED bulbs or fluorescent compact bulbs incandescent are all small gestures that help combat global warming.
The causes of climate change
Essential to life on Earth, the greenhouse effect is due to the natural occurrence of certain gases in the Earth’s atmosphere. Since the 20th century, it is accentuated by additional gas emissions related to human activities such as agriculture, the use of fossil fuels and industrial discharges. According to a vast majority of scientists, greenhouse surplus due to human activities played a key role in climate change in recent decades.
The greenhouse effect.
The greenhouse effect is a natural phenomenon, whose physical mechanisms are understood by studying the transfer of radiation. The atmosphere lets through a portion of the radiation of the Sun, which heats the surface of continents and oceans. These surfaces emit infrared radiation into the atmosphere. Atmospheric greenhouse gases absorb some of this radiation (which warms the lower layers of the atmosphere) and re-emit a part to the workspace. When the concentration of greenhouse gases increases, a larger portion of the infrared radiation is trapped in the lower layers of the atmosphere, which heats up; on the other hand, the upper layers of the atmosphere to cool. The comparison with the operation of a greenhouse gardener to view this phenomenon, but the mechanisms involved are of course not identical!