An Inconvenient Truth An Introduction to our Environmental

An Inconvenient Truth An Introduction to our Environmental Unit

Threats of Global Warming in Our Future Most global warming emissions remain in the atmosphere for decades or centuries. The energy choices we make today greatly influence the climate our children and grandchildren inherit. We have the technology to increase energy efficiency, to significantly reduce emissions from our energy and land use, and to secure a high quality of life for future generations. We must act NOW to reduce dangerous consequences.

Remember the hole in the ozone layer? What happened to it? In 1987, the nations of the world came together to draft the Montreal Protocol which would phase out the production and use of CFCs (chloral floral carbons). The 43 nations that signed the protocol agreed to freeze consumption and production of CFCs. The alarming loss of ozone in Antarctica and worldwide continued into the 1990's, and additional amendments to further accelerate the CFC phase-out were adopted. The pesticide methyl bromide, another significant ozone-depleting substance was phased out at the end of 2005. The Montreal Protocol is working and ozone depletion, due to human effects, has decreased and will keep decreasing in the next 10 years. Provided that the Montreal Protocol is followed, the Antarctic ozone hole is expected to disappear by 2050.

Global Warming Strong evidence that warming is attributed to human activities include: – – – Loss of polar ice sheets. Global sea levels rising. Plants and animals changing range and behavior in response to global temperature shifts. – Plants and animals dying and relocating. – Global temperatures rising yearly.

What is the Greenhouse Effect? The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder. These gases are referred to as greenhouse gases because of how they warm the Earth. The greenhouse effect maintains a livable temperature on Earth. Generally, the Earth is in balance. Problems arise when concentrations of CO 2 (carbon dioxide) and other greenhouse gasses increase. Who increases CO 2?

The Water Cycle & Carbon Cycle Water Cycle Animation Carbon Cycle Animation

Increasing Emissions Since the industrial revolution, greenhouse gases have increased by: Carbon Dioxide 30% Methane 100% Nitrous Oxide 15% (The graph shows PPM, parts per million, how gases are measured in the atmosphere. )

Human Contribution to CO 2 Humans are emitting more greenhouse gases into the atmosphere than ever before. We are wasteful with our resources. Cars, trucks, home and business heating, and power factories are responsible for about 98% of US carbon dioxide (CO 2) emissions and 18% of nitrous oxide missions.

Fossil Fuel Emissions per American have increased (per person). Most of these emissions, about 82%, are from burning fossil fuels to generate electricity and power our cars. Remaining emissions are from methane from wastes in our landfills, raising livestock for food, natural gas pipelines and coal.

Projected Future Emissions World carbon dioxide emissions are expected to increase by 1. 9 percent a year between 2001 and 2025. Much of the increase in these emissions is expected to occur in the developing world where emerging economies, such as China and India, fuel economic development with fossil energy. Developing countries’ emissions are expected to grow and surpass emissions of industrialized countries near 2018. Why? The U. S. produces about 25 percent of global carbon dioxide emissions from burning fossil fuels; primarily because our economy is the largest in the world and we meet 85 percent of our energy needs through burning fossil fuels.

Warming of Oceans comprise 97% of Earth's water. They have an average depth of approximately 13, 000 feet. It takes a great deal of heat to raise the temperature of this huge body of water, and the oceans have absorbed the bulk of Earth's excess heat over the past several decades. These are estimates of the Earth’s heat balance.

Glacial Melting § If only a small fraction of the heat currently stored in the oceans were released, it would significantly warm the atmosphere and melt the world's glaciers. Why do we need glaciers? § In reality, the circulation and redistribution of this excess heat is a slow process. Even if we could maintain atmospheric CO 2 concentrations at today's level, stored heat released by the oceans will cause Earth's average surface temperature to continue rising approximately one degree Celsius in the coming decades. What is C compared to F in temperature? § To put this into perspective, this is the same as the global average temperature rise that has occurred over the last century. The warming of the oceans and the melting of glaciers, worldwide, have already caused sea levels to rise, and most of this rise has come in the past few decades (how long is a decade? ). § CO 2 trapped in glaciers will also be released, as they melt due to higher temperatures, and this will cause a BIG increase when it happens.

Melting of Snow & Ice Half of Greenland’s ice sheet naturally melts every summer. But, in July 2010, 97% of the ice sheet had melted. The extent and duration of frozen ground have declined in most locations. Alpine and polar glaciers have retreated since 1961, and the amount of ice melting in Greenland has increased since 1979. Over the past 25 years, the average annual Arctic sea ice area has decreased by almost five percent and summer sea ice area has decreased by almost 15 percent. The collapse of the Larsen Ice Shelf off the Antarctic Peninsula appears to have no precedent in the last 11, 000 years.

Can 1 degree C really make a difference? Pasterze Glacier in Austria 1875 vs. 2004

Portage Glacier in Alaska 1914 vs. 2004

Mount Hood in Oregon 1984 vs. 2002

Recent Activity – Canadian Glacier On January 4 th, 2006 it was reported that a giant ice shelf the size of 11, 000 football fields snapped free from Canada's Arctic. Scientists say it was the largest event of its kind in Canada, in 30 years, and they point to climate change as a major contributing factor. They added that “the remaining ice shelves are 90 percent smaller than when they were when first discovered in 1906. ” "We aren't able to connect all of the dots. . . but unusually warm temperatures definitely play a major role. “ Blog Antarctic Ice and Pictures

Recent Activity - Droughts We have certainly seen global temperature increases and changes in precipitation patterns over the 20 th century, resulting from human activities. This has resulted in some increases in extremes of temperatures and precipitation. These trends will continue in the future, and there is concern that global warming will cause climate variability and extreme events (e. g. , floods, droughts, heat waves) to increase. For instance, a scientific analysis indicates human-induced climate change likely increased the severity of the 2003 European heat wave that killed thousands of people. The same study predicts that as climate change progresses, similar heat events will become normal rather than exceptional.

Recent Activity - Smog Right away, we should put existing technologies for building cleaner cars and more modern electricity generators into widespread use. We need to reduce pollution/smog. We can increase our reliance on renewable energy sources such as wind, sun and geothermal. And, we can manufacture more efficient appliances and conserve energy. (Do you have Energy Star appliances? What are these? )

Recent Activity - Storms In terms of overall hurricane activity (the number of and intensity of storms), the 2005 Atlantic hurricane season was the most active season on record. Because of the link between higher ocean temperatures and hurricanes, there is speculation that hurricanes will increase in frequency or intensity in a warmer world, with higher wind speeds and greater precipitation. Scientists believe that global warming will result in more intense hurricanes, as increasing sea surface temperatures provide energy for storm intensification. Higher ocean temperatures may also influence the tracks of hurricanes, increasing the likelihood of hurricanes through the Caribbean or hurricanes making landfall on the east coast (did this happen recently? !). Although his phenomenon is not very well understood, a track of unusually deep and warm water appears to have led Katrina directly to the Gulf Coast when it struck Louisiana and Mississippi.

Rising Sea Levels It is likely that much of the rise in sea level has been related to the concurrent rise in global temperatures over the last 100 years. On this time scale, the warming and the consequent thermal expansion of the oceans may account for about 27 cm of the observed sea level rise, while the observed retreat of the glaciers and ice caps may account for about 2 -5 cm. The rate of observed sea level rise suggests that there has been a net positive contribution from the huge ice sheets of Greenland Antarctica. Computerized Rising Sea Level Prediction Article and Pictures

Warmest Years on Record • • 13 of the 14 warmest years on record occurred this century, according to the UN. They said last year continued a long-term warming trend, with the hottest year ever in Australia and floods, droughts and extreme weather elsewhere around the world. 2001 -2010 was the warmest decade on record, the last three decades had been warmer than the previous one. The WMO's secretary-general, also said there had been no 'pause' in global warming, as has been alleged by climate change sceptics. “There is no standstill in global warming. ” Arctic sea ice in 2013 was at the sixth lowest on record. The WMO noted all seven of the lowest Arctic sea-ice extents took place in the past seven years, starting with 2007, which scientists were "stunned" by at the time. "Many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change. We saw heavier precipitation, more intense heat, and more damage from storm surges and coastal flooding as a result of sea level rise.

Our Changing Climate Global mean surface temperatures have increased 0. 5 -1. 0 deg C since the late 19 th century The 20 th century’s 10 warmest years have occurred in the last 15 years!

Possible Scenarios A warmer climate could result in less winter snowfall, more winter rain, and faster, earlier spring snowmelt runoff. In the summer, without increases in rainfall of at least 15 -20%, higher temperatures and increased evaporation could lower stream flows and lake levels. Less water would be available to support irrigation, hydropower generation, public supply, fish and wildlife habitat, recreation and mining. Possibility of higher risk of debris flows.

Agriculture is strongly influenced by climatic conditions and water availability. As climate warms, production patterns could shift northward and to higher elevations. Increases in climate variability could make adaptation by farmers more difficult. Warmer climate and less soil moisture may require additional irrigation.

Forestry Depending on the amount of climate change, the extent of forested areas could change little or decline by as much as 15 -30%. Hotter, drier temperatures could increase frequency of wildfires. Insect outbreaks carrying disease could increase with warmer, drier conditions.

How do we know all of this? Scientists have to think like detectives. They look for clues to help them understand how the world works. Then they investigate the clues to find evidence – real facts that can give them a better idea of what is going on. Here are some of the ways that scientists gather evidence about climate, both past and present: – Weather stations – Weather balloons – Ocean buoys – Sediment analysis – Tree rings Weather stations, balloons, ocean buoys, and satellites tell us the Earth’s temperature today. Ice cores, sediment layers, and tree rings tell us about what the Earth’s climate has been like in the past. With this evidence, scientists are learning how climate changes over time.

“How far can it go? The last time the world was three degrees warmer than today – which is what we expect later this century – sea levels were 25 m higher. So that is what we can look forward to if we don't act soon…I think sea-level rise is going to be the big issue soon, more even than warming itself… How long have we got? We have to stabilize emissions of carbon dioxide within a decade, or temperatures will warm by more than one degree. That will be warmer than it has been for half a million years, and many things could become unstoppable. …We don't have much time left. ” Dr. James Hansen, Director, NASA Goddard Institute for Space Studies. – The Independent 2/ 17/2006

Take Action at School! Throughout history, students have been the driving force in social change. Now more than ever is the time for students across the country to become global warming activists and join the movement. – Join the Virtual March – Encourage Your Mayor to Take Action – Watch An Inconvenient Truth – Replace School Lightbulbs – No Idling! – Recycle – Cut Back on Paper – – – – Educate Your Parents Use Timers Take Action at Home No Waste at School Meals and Events Plant Trees Conduct a School Energy Audit Replace Oil Burning Furnaces Spread the News Start a Club Speak Out Reward the Use of Hybrids Audit Student's Energy Use Review School's Purchases Carpool

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