Module 7.2 Weather And Climate Analysis

Chapter 7
2. Concept: Key factors that influence an area’s climate are incoming solar energy, the earth’s rotation, global patterns of air and water movement, gases in the atmosphere, and the earth’s surface features. It is important to understand the difference between weather and climate. Weather is a set of physical conditions of the lower atmosphere, including temperature, precipitation, humidity, wind speed, cloud cover, and other factors, in a given area over a period of hours or days. Weather differs from climate, which is the general pattern of atmospheric conditions in a given area over periods ranging from at least three decades to thousands of years. In other words, climate is the sum of weather conditions in a given area, averaged
Concept: The projected rapid change in the atmosphere’s temperature could have severe and long-lasting consequences, including increased drought and flooding, rising sea levels, and shifts in the locations of croplands and wildlife habitats. Climate models indicate that, in the worst-case scenario, we could face floods in low-lying coastal cities, forests being consumed in vast wildfires, grasslands turning into dust bowls, rivers drying up, ecosystems collapsing, the extinction of up to half of the world’s species, more intense and longer-lasting heat waves, more destructive storms and flooding, and the rapid spread of some infectious tropical diseases. If the models are correct, we will have to deal with many of these disruptive effects within this century—an incredibly short time span in terms of the earth’s overall climate history. In anticipation of such possibilities, scientists have identified a number of tipping elements, or components of the climate system that could pass climate change tipping points—those thresholds beyond which natural systems could change for hundreds to thousands of years, with possibly catastrophic effects. One such tipping element is atmospheric levels. A number of scientific studies and major climate models indicate that we need to prevent levels from exceeding 450 ppm—an estimated tipping point beyond which we might experience large-scale climate changes that would last for hundreds to thousands of years. We have already reached 400 ppm, and without strong efforts to improve energy efficiency and replace fossil fuels with low-carbon energy resources, we could exceed 450 ppm within a couple of decades. Another tipping element is global average atmospheric temperature. Several findings related to atmospheric warming are leading some scientists to suggest that we can no longer avoid a global temperature rise of more than, the threshold beyond which many say climate change will be very dangerous. Several of the effects of climate