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Well, we're moving on to the final unit. Global warming. I'm sure you have heard something about global warming. But what does a little temperature change mean to our world? And how does such a thing happen? Is it an effect of humans on the planet or not? I hope to get to all of these issues as we go through lessons on the diversity of our world, ecology, animals, and plants. Chapter 15 (which we will cover in Lesson 12) includes a bit of a description of global warming. Take a look at section 15.4.5 to begin to read about global warming. You will see that normally two things are occurring at the same time to our planet to affect its temperature:
However, if something interferes with one of these two processes, the Earth will not properly regulate its temperature. Where we think global warming is occurring is on the second process-- humans are potentially interfering with heat loss. You see, for heat to be lost, heat waves have to travel out of our atmosphere. Humans have been slowly mucking up the Earth's atmosphere. We have put a lot of CO2 into the atmosphere, and this gas can reflect heat waves back to Earth that would otherwise be lost. We will spend time talking about carbon dioxide in Lesson 12, so it will become more clear how we add it to the atmosphere. However, let me just say that scientists are not all sure that global warming is really occurring. It might not be happening at all. I'll come back to this idea. Finally, if global warming is occurring, it would affect all living organisms. Some would die out, some would survive, others might change (evolve). But everyone would be affected. Even if an organism isn't directly affected, it might be indirectly affected if its main food source dies out. It gets pretty involved... but you will be learning about all of this as we go on. So, keep going with the lessons! Lessons in this unit:
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© 2006 STCC Foundation Press, content by Dawn A. Tamarkin, Ph.D. Last changed: January 21, 2007 |
