Presentation on theme: "Climate change It is very likely that, overall, human activities since 1750 have had a global warming effect on the Earth. The Earth’s climate is influenced."— Presentation transcript:
Climate change It is very likely that, overall, human activities since 1750 have had a global warming effect on the Earth. The Earth’s climate is influenced by many factors, mainly by the amount of energy coming from the sun, but also by factors such as the amount of greenhouse gases and aerosols in the atmosphere, and the properties of the Earth’s surface, which determine how much of this solar energy is retained or reflected back to space. Sahara – years ago and now
Climate change Greenhouse gases such as carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) have significantly increased since the beginning of the industrial revolution. This is mainly due to human activities, such as the burning of fossil fuels, land use change, and intensive agriculture. Greenhouses in Alméria (Spain) – producing of tomatoes, cucumbers
Climate change – Greenhouse effect The surface of the earth is heated by the sun. As it warms up, it reflects heat back into the atmosphere. Water vapour, carbon-dioxide and methane form a natural blanket of air around the Earth. However, the burning of fossil fuels and deforestation has led to a massive increase in the amount of carbon- dioxide released into the atmosphere. We are also releasing larger quantities of other greenhouse gases, such as methane and nitrous oxide.
As a result of the greenhouse effect, the Earth is kept warm enough to make life possible. But some scientists say that increased emissions of greenhouse gases are disturbing the balance of this complex system, causing global warming. In the last 100 years, the average global temperature has increased by about 0.4 to 0.8° C. About 70% of the sun's energy is radiated back into space. But some of the infrared radiation is trapped by greenhouse gases, which warm the atmosphere, and reflect heat back down to Earth.
Climate change – Greenhouse Gases Emissions Expressed in Giga tonnes of CO 2 equivalent per year which includes different greenhouse gases scaled using global warming potentials. (Note: 1 Giga tonne = tonnes)
Climate change 1.Temperature 2.Sea level 3.Snow cover From 1850 to 2000
Climate change - problems Sea level rising – people are loosing their homes - migration More rain in rain forrests and higher latitudes – risk of floods Less rain in middle latitudes and low semideserts – lack of water
Climate change - problems Continental and mountain glaciers melting Animals are loosing their habitats – higher extinction and new habitats colonization Glacier Rongbuk (near Everest in 1921 and 2008)
Climate change - problems More diseases and deaths caused by extreme hot, floods, droughts, fire.... Changes in insect habitats and thus occurence of some diseases (malaria, tropical fevers,...)
Soil 1 Humus 2 Arable soil 3 Subsoil 4 Fragments of stale rock 5 Bedrock Soil – nonrenewable source Threats to Soil: -Erosion -Desertification -Pollution – salinization, chemical substances -Deforestation Loss of soil in large surfaces is non- returnable (Syria)
Erosion loss of upper layer of soil caused by deforestation or bad agriculture habits (trees stabilize this layer) and rain or wind. Some types of soil are more endangered (loess). Bad agriculture habits – slope fields, large fields withour ridges, some crops (corn, potatoes, sunflower, hop) Loess erosion in slopes, China Intensive agriculture in extreme slopes, Virunga, Rwanda
Desertification Desertification is the persistent degradation of dryland ecosystems by variations in climate and human activities. Desertification is caused by a combination of social, political, economic, and natural factors which vary from region to region It threatens the livelihoods of some of the poorest and most vulnerable populations on the planet. Desertification is largely caused by unsustainable use of scarce resources. Some 10 to 20% of drylands are already degraded, and ongoing desertification threatens the world’s poorest populations and the prospects of poverty reduction. Therefore, desertification is one of the greatest environmental challenges today and a major barrier to meeting basic human needs in drylands
Present – day drylands and their cathegories
Desertification Progressive enlarging of desert and lossiong of soil Steps against desertification -Better water using -Afforestation = soil protection -Stone lines building -Barrier building (sand dunes stabilization) -Increasing the value of soil by nature fertilizer, composting (humus layer enlarging) - Soil property assessment The same place in Burkina Faso in 1986 (in photo)
Salinization Destruction of soil caused by salts (natural, artificial) Salts are brought to soil by water (evaporates, not enough to take the soils away) Usually irrigated or arid areas Overexploiting of water sources Makes cultivation impossible
Global problems by 200 researchers from 50 countries
Population Limits to Growth (1972) – Rome Club Industrial growth must be stopped (no natural sources) Natality Mortality Children/woman –blue = 0-1, violet = 7 and more
Population Urbanization – 1800 = 3% of population in cities = 51% Migration to the cities = slumms, lower life standard, New work places needed = low earning = increase of poverty Age pyramids: developed countries and less developed countries (young population) Slumm in Mexico City
Sustainable development Sustainable development is a pattern of resource use that aims to meet human needs while preserving the natural environment so that these needs can be met not only in the present, but in the indefinite future. The term was used by the Brundtland Commission which coined what has become the most often-quoted definition of sustainable development as development that "meets the needs of the present without compromising the ability of future generations to meet their own needs.„ The field of sustainable development can be conceptually broken into three constituent parts: environmental sustainability, economic sustainability and sociopolitical sustainability.
Sustainable development Economic Sustainability: Agenda 21 clearly identified information, integration, and participation as key building blocks to help countries achieve development that recognises these interdependent pillars Sustainable development is an eclectic concept, as a wide array of views fall under its umbrella. The concept has included notions of weak sustainability, strong sustainability and deep ecology. Different conceptions also reveal a strong tension between ecocentrism and anthropocentrism. Thus, the concept remains weakly defined and contains a large amount of debate as to its precise definition.
Sustainable development Questions about Natural sources Population growth Food problem Biodiversity and Ecosystem preservation Energy consumption Waste production and degradation Global social problems Can be development uninterrupted?
Ecological footprint - Sustainability The ecological footprint is a concept that calculates the area of land and water needed to sustain a defined human poulation, based on the population’s use of energy, food, water, building material and other consumables. In 1961 humanity was globally using about half of the Earth’s capacity to renew its natural resources. Now this capacity is exceeded, and overuse is still growing
National Footprint Czech Republic Greece Portugal Norway