Global warming and climate change

Transcription

1 Chapter 2 Global warming and climate change Introduction This chapter provides resource material to create energy awareness the link to environmental pollution global warming and its impact on climate change The resources are compiled to stimulate discussion amongst students provide the appropriate background to an activity help the students identify ways in which they and their families can save energy Each lesson should involve both a discussion and an activity phase usually in the form of a group. Other activities are best done at home for which the resources also provide some background for parents. These resources can be supplemented where necessary from other sources such as articles in newspapers, magazines, news on TV or web based sources The ultimate goal is to challenge each student to do something to reduce their energy usage so we can all benefit by reducing the impact of global warming

2 2.1 Energy Awareness We all use energy from the moment we wake up until we go to sleep and even whilst we are sleeping. We use it to drive our cars, lighten our nights, clean our cloths, operate our computers, watch TV and make our homes warm and comfortable. Energy is abundant and cheap, cheaper than it has been before and we are so dependent upon it that we hardly notice its existence However it is a crucial aspect in our lives as we are so heavily dependent on, but what is it really and how much do we know about it? What is energy? Energy makes the things happen around us; Consuming food and water provides us with energy which allows us to get out of bed in the morning walk, run, play, think, do your homework, clean your room It is almost in everything: During the day, the sun gives out light and heat energy. This energy helps us directly or indirectly to make our lives easier and more comfortable; we use energy to run our cars, in school, provide lighting cooking food And the list goes on and on Energy can be defined as the ability to do work Where do we get energy from? Almost all energy comes from the Sun. The Sun warms our planet and makes plants grow. Plants use the Sun s energy not only to enable them to grow, but also to store energy. Animals and humans eat plants which in turn provide energy. One may get ones energy from eating fish which in turn ate smaller fish, which ate tiny plants called plankton. This is called a food chain. Where and how do we use energy?

3 People have learned how to use energy a long time ago. They used fire for lighting, heating and cooking food for thousands of years. They used wind to sail their ships and grind grain People have learned how to use energy to do so many things that weren t possible before, such as; lighting our cities warming our homes and cooking our food powering our cars, trains, planes and boats playing our music and watching television powering machinery in factories and tractors on a farm making all kinds of products like shoes, CD's, books, computers and scooters transporting our food, cloths, books, televisions communicating using our telephones, radio, television, internet 2.2 Sources of energy Much of our energy come from under the ground by releasing ancient energy stores called fossil fuels - made by billions of tiny plants and stored by animals, which lived millions of years ago. These fuels are called coal, oil and gas. All of them come from underground, inside the Earth's crust. These resources are used to make electricity in power stations natural gas to heat our homes and warm water petrol or oil for most forms of transport and all of the fossil fuels are used in power stations to produce electricity

4 However there are other resources which are renewable which we will increasingly need to use, such as Hydropower: uses water to produce electricity Windmills: produces electricity from wind power Solar thermal panels: use sun's rays to heat water Solar photovoltaic: produce electricity from sunlight Biomass: use wood for heating and cooking 2.3 Causes of global warming Everybody is talking about global warming and how it will change our planet and our lives. However not everyone understand the causes nor the possible consequences. Some of the facts about global warming are summarized below which has strong scientific evidence to confirm these findings. What is it? The climate of the Earth has been changing rapidly It has warmed by about 0.7C over the last 300 years Scientists believe that it will get much warmer (from 2C to 5C) by the end of this century called global warming This temperature rise is However climate change might be a better description as various countries might be affected in different ways

5 Why is it happening? Most scientists agree that human now have a significant influence on climate through increasing population and increasing use of energy It occurs primarily because additional greenhouse gases are being emitted to the atmosphere These greenhouse gases include CO 2, methane, nitrous oxide, ozone, and are created by human activities like fossil fuel consumption, deforestation methane emission due to decay of vegetation and landfill 2.4 Impacts of climate change What is wrong with a warmer climate? There are many consequences of global warming which we may need to worry about. Although 5 degree temperature rise may not seem too much in cold countries it would change the entire climate system. It is also seems to be happening so fast that ecosystems will not have time to adapt. Some of these changes are listed below; More rain/more storms Warmer temperatures increase the energy of the climatic system and lead to more intense rainfall in some areas due to higher evaporation of water from lakes, rivers and seas The amount of rainfall may also change in specific areas and could affect up to 3 billion people or half the population of the planet

6 More droughts/more wildfires Climate change wills almost certainly induce changes in where the rainfall falls. Greater evaporation, particularly during summer and autumn, can worsen drought conditions and increase the risk of wildfires Many people in places like Asia and Africa may not be able to grow the crops they need to survive so there could be more famines Heat waves and the spread of disease More often and more severe heat waves could result in more heat-related deaths as we experienced in the very hot summer of 2003 throughout Europe. Diseases, like malaria, that prefer hot temperatures may spread to more places in the world as the temperature goes up. Melting glaciers, early ice thaw Rising global temperatures will speed the melting of glaciers and ice caps and cause early ice thaw on rivers and lakes. The ice sheet now covering Greenland may partly melt which will add water to seas and will cause higher sea levels. Melting mountain glaciers will also add more water to the seas.

7 Sea Level Rises As temperatures rise, the sea will absorb more heat from the atmosphere, causing it to expand and therefore creating sea level rises. The outcome of these impacts is that the level of the sea may rise by 10 cm - 90 cm. Places like London, New York may be partly submerged by 2050 unless very expensive barriers are erected. Ecosystem shifts and species die-off The increase in global temperatures is expected to disrupt ecosystems and result in loss of biodiversity as species that cannot adapt sufficiently fast, die off. An extensive study of the extinction possibility from global warming found that more than one million species could be extinct by 2050 if global warming is not halted. Species like coral reefs are already in danger as higher temperatures damages them.

8 2.5 Reducing global warming The international community has already taken action to reduce global warming by ratifying the United Nations Framework Convention on Climate Change. The ultimate objective of this convention is the stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow eco-systems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner The EU and its member states have already taken action to meet their commitments under the Kyoto treaty to reduce greenhouse gas emissions and the target for the EU as a whole is 8% reduction by As the main cause of global warming is greenhouse gas emissions congregating in the earth's atmosphere, the key rule is to use less energy particularly that derived from fossil fuels. As fossil fuels are used to generate electricity and provide energy for heating and transport, an obvious way to save energy is to use it more efficiently and to identify ways of saving it. 30% of all energy in Europe is used in the home and so the home and school are the obvious places to start. The activities described in chapters 5, 7, 8 and 9 illustrate ways of identifying where energy is used in the home (or school) and how it can be saved. The Kyoto target will only be met if everyone does their share to use energy more efficiently 2.6 Additional information What is global warming? Global warming refers to an increase in global average temperatures. Scientists infer that the Earth has been warming up faster than it has in the last thousand years. Temperature measurements taken by instruments all over the world shows that there has been a gradual increase in average temperatures during the 20th century, the Earth s surface and lowest part of the atmosphere have warmed up on average by about 0.6 C. What are the causes of global warming Global warming is considered to be due to increases in greenhouse gas emissions, mainly carbon dioxide, methane, nitrous oxide and other greenhouse gases in the earth's

9 atmosphere. The increase in these gases is associated with the burning of fossil fuels for energy and transportation. Other causes of global warming include excessive agriculture, land use changes and deforestation. As a consequence, all these events have enhanced the Earth's natural greenhouse effect by increasing the greenhouse gas concentrations in the atmosphere. Influence of the Greenhouse effect The greenhouse effect plays a crucial role in maintaining a life-sustaining environment on the earth. If there was no greenhouse effect (supposing there were no greenhouse gases existing in our atmosphere), the temperature of the earth would be around 15 C 0, a very inhospitable, frozen world. However, the mean temperature of our planet averaged over the year is about +15 C 0. This difference is due to the greenhouse effect. Greenhouse Effect Water vapour, carbon dioxide, methane, nitrous oxide and other greenhouse gases form a natural blanket of air around the Earth. In simple terms, sunlight passes through the atmosphere, warms the Earth. In turn, the Earth radiates this energy back towards space. As it passes through the atmosphere, greenhouse gases absorb part of the energy, whilst the remainder escapes into space. This result in some of the sun's energy becomes trapped thus making the lower part of the atmosphere and the Earth warmer. Consequences of global warming Temperature rise: In the last 100 years the Earth s average temperature has risen by 0.6 C. If the climate changes as computer models predict, then global average surface temperatures could be C higher by the end of the 21st century than in The areas most likely to be affected by temperature increases are the northern polar zone and the continental interiors in the mid-latitudes. Surprisingly, according to results from new circulation models, the southern polar zone might experience a smaller increase in temperature. Extreme Weather Events Such a rapid change in climate will inevitably cause more extreme weather events including droughts, floods and associated landslides, storms, cyclones and tornadoes, ocean and coastal surges, heat waves and cold snaps. Wet areas are likely to become wetter, with more frequent incidents of flooding, whilst dry areas may become drier, with longer periods of drought leading to an increased threat of desertification. In general, as more heat and moisture is put into the atmosphere, the likelihood of storms, hurricanes and tornadoes will increase.

10 Frequent reports of record-breaking events suggest that climate extremes are becoming more common. Experts predict that fierce storms and floods are likely to become more frequent in the future Droughts, forest-fires, heat wave, floods and storms have all hit the headlines in recent years. In southeast England, local people say the floods of recent days are the worst for 40 years. (BBCnews, Tuesday, 17 October, 2000) As temperatures rise, droughts and heat waves will become more common. During the summer of 1998, the US experienced record temperatures, and more than 140 people died. The drought and searing heat also resulted in crop failure, with stunted crops in some areas yielding less than half of what they should. Wildfires raged throughout southern Europe and the Mediterranean last summer. More than 150 forest fires broke out in Greece alone. Conservationists say as temperatures rise, forest fires are set to worsen if more is not done to prevent them.

11 Rise in sea level, polar ice melting If the Earth's atmosphere warms as expected, ocean waters will also warm up and expand, taking up more space and causing sea level to rise. The ice sheet now covering Greenland would partly melt, contributing further to higher sea levels. Melting mountain glaciers would also add more water to the seas. Low-lying coastal areas worldwide would be flooded as the sea levels rise. And the rising oceans would surge farther inland during storms, adding to the problem of coastal flooding. Measurements during the past 100 years reveal that sea level has already risen worldwide by 10 to 25 cm. In the next century, rapid global warming could triple that rate. By 2050, the oceans may rise another 20 cm, causing low-lying shorelines to recede significantly. Vast coastal areas would be lost. Warmer Northern Polar Winters Winters in the northern polar zone could be 10 degrees warmer according to some studies. This increase in temperature could cause sea ice to melt, which will result in a rise in sea level. Temperatures around Antarctica have risen five times faster than the global average over the past 50 years, going up by around 2.5 C since the 1940s. The Arctic has also seen rapid warming.