Topic : Case Studies of Important Scientific and Technological Issues The Nature and Development of Science and Technology Global Warming

1. Is global warming really occurring?

Is global warming really occurring? What are the evidences proving it?

Temperature changes in different regions during the past 25 years

Global temperature changes in the past 140 years Temperature changes of the northern hemisphere in the past 1000 years

in the past 1 in the past 1 Change of precipitate in different regions the past 100 years

Changes in global surface temperature

Global warming does not exist! Although the global temperature is rising, global warming is not caused by human. How do the scientists obtain the information? Are the evidences from scientists reliable?

2. What are the main causes of global warming?

What are the main causes of global warming? Because the Sun releases more energy? Due to natural phenomenon? Maybe due to human factors?

Scientists believe of the reasons below : Changes of the distance between Changes of the distance between the Earth and the Sun the Earth and the Sun The amount of black spots on the Sun The amount of black spots on the Sun Plate tectonics movement and the change Plate tectonics movement and the change of the landscape of the landscape Volcano eruption that causes Volcano eruption that causes temperature decrease in the short-term temperature decrease in the short-term Greenhouse effect Greenhouse effect Natural phenomenon Man-made phenomenon

How is the Greenhouse Effect formed?

The Greenhouse Effect Some solar radiation is reflected by the Earth and the atmosphere. SUN 1. Solar radiation pass through the clear atmosphere Atmosphere EARTH 2. Most radiation is absorbed by the Earth’s surface and warms it. 2. Most radiation is absorbed by the Earth’s surface and warms it. 4. Some of the infrared radiation passes through the atmosphere, and some is re-emitted in all directions by greenhouse gas molecules. The effect of this is to warm the Earth’s surface and the lower atmosphere. 3. Infrared radiation is emitted from the Earth’s surface

In the atmosphere, the greenhouse gases are responsible for radiation absorption Composition of gases in the atmosphere

Major greenhouse gases Carbon Dioxide (CO 2 )Carbon Dioxide (CO 2 ) Source: Fossil fuel burning, deforestationSource: Fossil fuel burning, deforestation Anthropogenic increase: 30%Anthropogenic increase: 30% Average atmospheric residence time: 500 yearsAverage atmospheric residence time: 500 years Methane (CH 4 )Methane (CH 4 ) Source: Rice cultivation, cattle & sheep ranching, decay from landfills, miningSource: Rice cultivation, cattle & sheep ranching, decay from landfills, mining Anthropogenic increase: 145%Anthropogenic increase: 145% Average atmospheric residence time: 7-10 yearsAverage atmospheric residence time: 7-10 years Nitrous oxide (N 2 O)Nitrous oxide (N 2 O) Source: Industry and agriculture (fertilizers)Source: Industry and agriculture (fertilizers) Anthropogenic increase: 15%Anthropogenic increase: 15% Average atmospheric residence time: yearsAverage atmospheric residence time: years

Sources of Greenhouse Gases

Natural gases exploitation

Burning of fossil fuels Source: OSTP

Deforestation Source: OSTP

Vehicle exhaust

Thousands of years ago Temperature change ( °c) Carbon dioxide (ppmv) Temperature Change ( °c) CO 2 Concentration (Antarctic Ice Core) Current Level 1800 AD Atmospheric Carbon Dioxide Concentration and Temperature change Clear correlation between atmospheric CO 2 and temperature over last 160,000 years Current level of CO 2 is deviated from the nature Fast increase of CO 2 is also unprecedented Clear correlation between atmospheric CO 2 and temperature over last 160,000 years Current level of CO 2 is deviated from the nature Fast increase of CO 2 is also unprecedented

Thousands of years ago Temperature change ( °c) Carbon dioxide (ppmv) Temperature Change through time Compares to the present temperature Current Level Atmospheric Carbon Dioxide Concentration and Temperature change Current Level 2100 CO2 Concentration in the atmosphere (Antarctic Ice Core) If nothing is done to slow greenhouse gas emissions... CO 2 concentrations will likely be more than 700 ppm by 2100 Global average temperatures projected to rise at degrees If nothing is done to slow greenhouse gas emissions... CO 2 concentrations will likely be more than 700 ppm by 2100 Global average temperatures projected to rise at degrees

3. What are the influences of global warming to us?

The influences of global warming included: Individual health Water source Northern and Southern Poles Natural ecosystem Agriculture Forests Coastal areas

Health Weather-related mortality Infectious diseases Air-quality respiratory illnesses Agriculture Crop yields decrease Worsen quality Water Resources Changes in water supply Water quality Increased competition for water Coastal Areas Erosion of beaches Inundation of coastal lands Costs to protect coastal communities Forests Change in forest composition Shift geographic range of forests Forest health and productivity Species and Natural Areas Shift in ecological zones Loss of habitat and species Potential Climate Change Impacts Sea Level Rise Temperature Precipitation

What are the measures applied to prevent global warming? What can we do?