Climate and weather both refer to atmospheric conditions, but climate represents conditions over years whereas weather includes conditions over a span of days. Earth is a sphere, has an atmosphere, and rotates around its axis, which creates latitudinal variation in solar radiation, temperature and precipitation, and prevailing winds and ocean currents. Earth’s tilt and orbit around the sun result in the seasons.
learning outcomes
You should be able to:
Compare weather and climate, and give examples of both.
Analyze differences in temperature at the equator and the poles as a function of Earth’s spherical shape.
Relate Earth’s ocean currents to prevailing wind patterns, and explain how ocean currents affect climate.
Connect the tilt of Earth’s axis and its orbit to the existence of seasons on Earth, and explain why the Northern and Southern Hemispheres have opposite seasonal patterns.
Does a month of extremely hot weather tell us that Earth’s climate is warming? Explain your answer.
No. A month of extremely hot weather does not necessarily tell us that Earth’s climate is warming. Climate is the long-
Why does solar energy input into Earth’s atmosphere vary with latitude? What are the consequences for global climate?
Because Earth is a sphere, the intensity of solar radiation hitting its surface varies with latitude. At high latitudes, incoming solar energy comes in at an angle and has to travel through more of the atmosphere than at the equator, making it less intense than at the equator, where sunlight strikes the surface perpendicularly. The consequence of this latitudinal variation in energy input is a major difference in temperature and precipitation at every 30° latitude. At the equator, climate is tropical with warm and wet conditions. At 30° N and S, climate is warm and dry, producing desert conditions. At 60° N and S, climate is temperate with cold and wet conditions. At the poles, climate is cold and dry.
Refer to Figures 53.6 and 53.7. If you were sailing, using wind power only, from the east coast of North America to Europe across the Atlantic Ocean, describe the best route given winds and currents.
If you were sailing from New York to the United Kingdon (west to east), you would want to use the Westerlies and the Gulf Stream to your advantage. Thus you would want to sail in a northeastern direction across the Atlantic Ocean. If you were sailing from San Francisco to Japan, you would want to take advantage of the NE Trade Winds and the North Equatorial Current in the Pacific Ocean.
Explain why Earth’s Northern and Southern Hemispheres have opposite seasons.
Earth’s axis is tilted, changing the amount of sunlight a particular region receives over the course of a year as Earth orbits the sun. When the Northern Hemisphere is tilted toward the sun, it experiences summer conditions, but that means that the Southern Hemisphere is tilted away from the sun and experiences winter conditions.
We have considered large, global patterns in climate, but we know that the physical environment can vary within certain regions or even locally. Just travel across a large mountain range and you can experience lush forests on one side and bone-