A current world debate

Colorado Prepared Graduate Competencies: Evaluate evidence that the Earth is a complex system of interactions between the geosphere, atmosphere, hydrosphere and biosphere. Concepts and Skills students know include: 4. Climate is the result of energy transfer among interactions of the atmosphere, hydrosphere, geosphere, and biosphere. Inquiry: How have climate changes impacted human society? Why are there different climates on Earth? How can changes in the ocean create climate change? How have climates changed over Earth’s history? How are humans potentially impacting Earth’s climates? How might global warming impact all of Earth’s systems?

Not debated: Climate has always changed throughout Earth’s history. Debated: Current climate change is due to man made causes. Current climate change is a part of Earth’s natural cycle. Versus In this lesson we will look at both sides of the debate

Review: Green House Effect  Without the greenhouse effect are planet would be cold and uninhabitable.

Interpreting CO 2 Data Part 1  Graph CO 2 data set.  This dataset from Mauna Loa is the most complete and accurate CO2 dataset in the world. CO2 is measured in parts per million; 316 parts per million means that for every 1 million particles in the atmosphere, 316 of those are carbon dioxide molecules.  Year should be on the x-axis and CO2 emissions on the y-axis. The scale should be appropriate for the data.  Include all graph requirements (title, labeled axis, etc…)  Line Graph (2 lines & 2 different colors)  Answer questions on the back of graph.

Analysis & Conclusions  What might account for differences in the CO2 concentrations measured in May and October of each year?  Based on the data shown on your graph, what do you think the carbon dioxide concentration will be in the year 2020?  Why do you think carbon dioxide levels have continued to rise during the past 45 years?  What types of activities might raise carbon dioxide levels even faster?  How do you think this will affect Earth’s climate?

Is current climate change man made?

Analysis & Conclusions  What conclusions can you draw from this graph?  Is the graph appropriate to make these conclusions?

Arguments For Human Caused Climate Change (Global Warming) FACTS  The burning of fossil fuels and the clearing of forests release carbon dioxide (CO2) into the atmosphere.  Carbon dioxide and other greenhouse gases in the atmosphere trap heat through the greenhouse effect.  Earth is warming because these gasses are being released faster than they can be absorbed by natural processes.  It is very likely (greater than 90 percent probability) that human activities are the main reason for the world's temperature increase in the past 50 years.  The rate of change in temperature is greater than and change in geological history.

Arguments For Human Caused Climate Change (Global Warming) Scientists know with very high confidence, or even greater certainty, that: (greater than 90 percent probability)  It is very likely that human activities are the main reason for the world's temperature increase in the past 50 years.  Human-induced warming influences physical and biological systems throughout the world  Sea levels are rising  Glaciers and permafrost are shrinking  Oceans are becoming more acidic  Ranges of plants and animals are shifting

Arguments Against Human Caused Climate Change (Global Warming)  Natural part of Earths cycle of climate changes.  The temperature increase is very small especially when it is spread over a century.  The earth was warmer before. That did not have harmful consequences on humans.  The increase in temperature will help plants grow in currently cold and uninhabitable areas.  The increase in the level of carbon dioxide will stimulate plant growth.  Steps to limit global warming will decrease economic growth and hurt the poor.  People in fossil fuel industries will lose their jobs.  Rise in carbon dioxide levels has always come after a temperature change and not before.  The upsurge in solar activity in the sun has caused global warming.  Water vapor plays a major part in global warming. It is argued that man made emissions like carbon dioxide has only minor effects.  The global warming is a natural phenomenon. Man has no role to play in it. Only our environment is responsible.

U.S. survey based on the opinions of 3,146 scientists. Two questions were key: 1. Have mean global temperatures risen compared to pre-1800s levels. 2. Has human activity been a significant factor in changing mean global temperatures?  90 percent of the scientists agreed with the first question and 82 percent the second  The strongest consensus on the causes of global warming came from climatologists who are active in climate research, with 97 percent agreeing humans play a role.  Petroleum geologists and meteorologists were among the biggest doubters, with only 47 percent and 64 percent, respectively, believing in human involvement. Study done by University of Illinois