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 – 8 000 years ago and now

Climate change

• Greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) 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 CO2

equivalent per year which includes different greenhouse gases scaled using global warming potentials.

(Note: 1 Giga tonne = 1 000 000 000 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 sourceThreats 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

DesertificationProgressive 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)

SalinizationDestruction 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 areasOverexploiting of water sourcesMakes cultivation impossible

global problem % climate change 51 lack of drinking water 29 deforestation / desertification 28 fresh water pollution 28 public domain bad shape 27 decreasing biodiversity 23 increasing population and migration 22 social values change 21 waste disposal 20 air pollution 20 soil degradation 18 ecosystems funktion 17 chemical pollution 16 urbanization 16 ozone depletion 15 energy consumption 15 new diseases 14 natural resources decreasing 11 food uncertainty 11

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• - 2010 = 51% • Migration to the cities = slumms, lower life standard, • New work places needed = low earning = increase of

poverty

Countriesbyfertilityrate.svg

Age pyramids: developed countries and less developed countries (young population)

Slumm in Mexico City

World population

Population (in

billions) 1 2 3 4 5 6 7 8 9

Year 1804 1927 1960 1974 1987 1999 2012 2027 2046

In …years –– 123 33 14 13 12 13 15 19

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 www.footprintnetwork.org/atlas

Czech Republic

Greece

Portugal

Norway