SCIN 137 AMU week 7 lesson GLOBAL CLIMATE & THE EARTH’S CHANGING CLIMATE
Introduction to Meteorology American Military university
- Lesson Overview
This is always a topic people become passionate about, and we will also explore it a bit more in next week’s lab. Discussions on Global Climate Change have become almost as delicate as discussing politics and religion (it’s still safe to talk about the “weather” though as that is not an indicator of climate change!). There are always people who “believe”, “disbelieve” or don’t know what perspective to take, so don’t worry about where you fall along that spectrum, focus on what the science you have learned tells you as well. There are aspects of personal philosophy, science and society that go into our perspectives, and they are all legitimate – don’t feel left out or “wrong” if yours are different than friends, classmates or others. Nobody can answer the global climate change “question” with 100% certainty – if someone says they can, they are deluded! We cannot predict the future, and we cannot begin to understand all of the past or present, so it really is a matter of understanding and interpretation of many variables to lead us to an educated position. MOST important is keeping in mind the difference between “weather” and “climate”. A hot day in your town doesn’t mean it is global warming, and a cold day doesn’t mean it isn’t global warming. That is “weather”. “Climate” is the long-term average of weather and other conditions.
Students will be able to:LO-45. Understand how climatology is different from weather. LO-46. Explain what factors produce the climate of a location on Earth. LO-47. Compare and classify the various climates of the world. LO-48. Understand that climate has changed in the past and is likely to change in the future. LO-49. Discuss the causes for climate to change. LO-50. Explain the greenhouse effect and nuclear winter
The following activities and assessments need to be completed this week:
- Read Barry and Chorley: Chapters 10 and 12.
- Research Project
- Week 7 Lesson
- Week 7 Forum
- Week 7 Lab
- Week 7 Quiz
- COMET Modules (Optional):
- Introduction to Climatology
- Weather is the atmospheric status at a particular place now and predictions of the future status for the next few weeks at most. Climate is the average atmospheric status over the long term, usually 30 years or more. This week’s lesson looks at the basic climate types, how they have changed in the past, and how scientists predict they will change in the future. We will look at global warming in depth and some consequences of climate changes. Climate change will be one of the most important issues in your future, no matter what your major is. Topics to be covered include:
- Climate classifications
- Global climate patterns
- Climate history
- Global warming
In the first lesson you learned that climate is not just the weather for a single season or year. You might have just lived through the coldest winter or warmest summer you ever remember, but one extreme season is not an indication that the climate has changed. Climate is the long term status, usually averaged over 30 years or more. Sometimes there are great differences in climate within a short distance, such as in the Pacific Northwest where Seattle sees less than 11 inches of snow in a winter while 50 miles away the ski areas in the mountains may have 30 feet of snow over the winter.
The conditions that determine climate, the climate controls, you have seen before as they are also the atmospheric factors that are responsible for each day’s weather:
- Solar intensity, which varies with the latitude
- Location with respect to continents and oceans
- Ocean currents
- Location with respect to the general circulation of the atmosphere
- Low and high pressure areas
- Topography such as mountains
- Human activity and changes
In earlier lessons, you have seen how natural changes influence the weather. We will look more deeply into human activities later in this lesson. For now, what do you think the effect is if a forest is cleared and converted to cropland or if a river is dewatered for irrigation or diversion to a far-away city, drying up a large lake? We will look at climate patterns concerning precipitation and temperature.
Looking Into the Past
Climate changes over time, an expected and natural process. However, cutting down forests and the production of greenhouse gases by human endeavors has led to warming of the world at a dire rate. The composition and temperature of the atmosphere is changing. We will take a hard look at the evidence and the causes of climate change. No one has any doubt that glaciers covered a great deal of the Earth around 20,000 years ago and periodically before that. In between the glacier advances the average temperatures were a bit warmer than the current averages, leading some scientists to believe are still in a warmer interval before a future ice age. At present less than ten percent of the Earth is covered by glaciers but they hold the majority of the world’s fresh water. Most of the ice is in the Antarctic and Greenland. If all the ice melted, the ocean would rise by about 213 ft (65 m). Much of Tokyo, London, and New York would be under water. That is not going to happen, but even an average rise of a few degrees can raise the ocean level by a few feet.
Man-Made Factors of Climate Change
As people continue to produce greenhouse gases, the Earth will warm. However, that is not the only man-made climate changer. Forests have a huge impact on weather and, ultimately, climate. Roughly half of the rain that falls in the Amazon watershed returns to the air via evaporation and transpiration from the trees. Clearing forests interrupts that process. Decreasing the amount of evaporative cooling could result it raising the temperature. The reflectivity of the area will change – when the fields are bare and dark in color they will absorb more of the sun’s energy than the shiny, green leaves.