Environmental Chemistry: Global Warming Yr 10 Chemistry Environmental Chemistry: Global Warming

Exam Question "Global warming is not real and no evidence exists that humans are causing temperature changes on the planet". Include in your answer: Include chemistry in your answer What is global warming? (Understanding) What gases cause global warming and why? (Understanding) Is global warming natural or man-made? (Understanding) What can we do to reduce its affect? (Understanding) Neat, organised, using subheadings. (Skills)

Give reasons for your answer Starter Which is the odd one out? Give reasons for your answer car volcano house

Challenge…………. Why does the inside of a car get hotter than the outside on a sunny day? Is the Earth getting hotter? If it is what is trapping the heat inside? (since the earth is not surrounded by a sheet of glass)

Global Warming Mind Map Prevention Definition How Global Warming Works. Global Warming Affects of Global Warming Gases that cause Global Warming Animals Plants Building Humans Man made sources

Objectives TO KNOW what is ‘global warming’ and greenhouse gases. TO BE ABLE to find ways to reduce global warming. TO UNDERSTAND how greenhouse gases cause global warming

Is Global Warming Real? As ‘scientists’ we need to answer this question in a logical way…. Is there a link between atmospheric gases and temperature? If so, what is the relationship? If so, what gases may be causing these changes. Once we understand these, the big question is…….. What is the impact of humans on this process?

Bias Lets start with what you think is happening. Write down your opinion to these questions? Is global warming real? Why? Are humans contributing to this? How?

Evidence 1: Recent rising temperatures Over the last few hundred years, the average temperature of the Earth’s oceans has been rising. This is global warming. Why is this a problem? Global warming increases the energy in the atmosphere, making it turbulent – more storms, more droughts, more floods.

Evidence 2 Is this just a natural change in temperature. We need to examine temperature over a much longer time. We need to examine if certain atmospheric gases maybe affecting it.

Measuring the gases in the tiny bubbles in these ice cores is a difficult process and determining the average global temperature can be done from the amount of ice present . 1. What trends do you see over the last 400 000 years? 2. Is there a correlation between CO2 levels and Temperature? 3. Which comes first CO2 levels or Temperature? 4. Why is #3 an important question to find an answer for?

Long Term Trends: What has happened to the Earth’s climate over many thousands of years? How do we know this? These are important questions if we want to know what the future climate of our Earth will be. One of the ways that scientists can measure Co2 levels and temperatures levels in the past is by looking at ice core samples from very old ice. Snow is laid down over the winter. The top layer is melted over the summer and then new snow piled up on top during the following winter. This causes some of the Earth’s atmospheric gases to dissolve in the melted ice and the ice to form bands or layers. We need very old ice to measure very old atmospheric gases. This is a ice core sample from Vostok Antarctic Base showing these bands:

Scientist have also been measuring the level of CO2 in the atmosphere for about as long as the temperature. Is there a relationship between CO2 levels and global temperature? Which comes first: Increase in CO2 levels or Increase in temperature? This is an important question! No body disputes that the Earth is warming up. Six of the hottest years on record have been in the last decade. What scientist are still debating is the cause or more importantly how much of this heating up is due to human activities and how much is “natural”. The Kyoto Protocols (of which Canada signed in 1997 and came in force in 2005) has set targets to reduce CO2 gases to 1990 levels. Why would we want to do this? This is an expensive proposition (we all are now paying a Carbon tax). What if the basic idea is incorrect?

The Key Greenhouse Gases A greenhouse gas is a gas in the atmosphere that reflects infrared radiation back to Earth. Do these gases act as greenhouse gases in the atmosphere? Answer ‘yes’ or ‘no’. gas greenhouse gas? carbon dioxide methane CFCs ozone nitrogen oxide yes yes yes yes yes One of these gases in particular is on the rise, causing the ‘enhanced greenhouse effect’. Which gas? What processes produce this gas?

What about the greenhouse effect? The greenhouse effect is a theory to explain why global warming is happening. Light reaches us from the Sun. Some of it is absorbed by the Earth and warms it. Some is reflected back into space. With more greenhouse gases, more infrared is reflected back to the Earth, and it gets warmer still. Some infrared radiation is reflected back by the greenhouse gases. This makes the Earth warmer than it would be without the greenhouse gases. The Earth gives off infrared radiation because it has been warmed by the Sun. In the atmosphere is a layer of greenhouse gases. How does the greenhouse effect explain global warming? The world needs the greenhouse effect. Without it the Earth would be too cold for most organisms to live.

Erratic precipitation Sea level Rise Erratic and more intense Weather Consequences for Climate Change: Temperature Change Erratic precipitation Sea level Rise Erratic and more intense Weather

China 2010 : Over 700 killed and millions displaced from their homes 1) Temperature Change: The Earth’s climate is driven by solar radiation, the Earth’s spin, and the average global temperature. Any changes in these factors will cause significant changes in the weather patterns. imagine what would happen to all the farmers in Africa if the yearly rains stopped coming? Or if the yearly rains in India came in twice the amount for twice as long? What would happen to our river and streams if all of our glaciers melted? What would happened to our forests if the rains decresed by a significant portion?

2) Erratic Precipitation: In many places in the world farming is a marginal proposition. The farmers depend on rains that may come only once a year. What happens when those rains fail to appear? In the 1930’s the rains for the Mid-West in North America failed to come. Many farmers had their farms dry up. This created the infamous “Dust-bowls of the 1930’s”.

The ocean warming up and is rising! Why is this a problem? 3) Sea Level Rise: This used to be an island! Do Worksheet on Ocean Rise.

4. Erratic and more intense Weather Hurrican Katrina (2005) China Flood 2010)

? This what scientist are trying to find out! The big questions still remains: How much of the Earth’s climate change is anthropologic? If a significant amount of climate is due to the increasing use of fossil fuels (and other human activities), can we alter human activities to lower the human effect? ? If the human factor is an insignificant effect then what can we do? This what scientist are trying to find out!

Activity: Write a sentence for each term as it relates to Global Warming Carbon dioxide Greenhouse gases Methane Infrared radiation Fossil fuels Coal Oil Atmosphere Rainforest destruction Temperature  

Activity: Write a sentence for each term as it relates to Global Warming Carbon dioxide Greenhouse gases Methane Temperature Infrared radiation Core samples Fossil fuels Coal Oil Atmosphere Rainforest destruction   Using what you have written, construct a quick mind map.  

Informed Response Write down your opinion to these questions? Is global warming real? Why? Are humans contributing to this? How? Has your opinion changed? How has your answer changed?