Hey there explorers, it's Bryan here with you for another adventure around the world.
Look closely at this map of the world. You'll notice I've left off the title and a key. What
information do you think this map displays? Go ahead, look for clues. You might notice that
China and India have regions that are especially dark and you might see that much of north Africa,
Australia, Russia, and Greenland are very light in color.
If you haven't already completed the preview activity, pause the video here and write a
prediction about what you think this map is intended to show on the preview page of your PDF.
Make sure to cite some evidence from the map to explain your reasoning.
Let's zoom in on the U.S. to see if we can figure this out. See the dark purple spots dotting the
country? There's one here, another one here, and here. There's a whole darkly shaded region up in
the northeast. Conversely, a lot of the west is pretty light in color until you get out toward the
coast where you can see much of California and some areas further north with dark coloration.
What do you think the dark areas represent?
If you wrote in the preview that this map shows where people live you're absolutely right! If this
map had a title, it would be "Global Population Density". The more people that live in a place,
the darker the coloration appears on the map. You might even be able to spot a city near you.
It's no surprise that China and India stood out to us from the beginning. These two countries
are some of the most densely populated and of the world's only two countries with over
a billion people. And we noted that North Africa and Australia were sparsely populated,
but why? Well to answer that we may need to take a look at another map.
Join me as we visit some diverse biomes around the world. Ready explorers?
Today's objectives are to identify the five
climate regions in the Köppen climate classification system,
to discuss their features, and to review the geological factors that cause them to exist.
And that brings us to a new map, the Köppen Climate Map. If you still have the population
density map fresh in your mind or the PDF image in front of you, compare the maps briefly. Pause
the video and note some similarities in the two maps on your lesson guide on Page 3.
Obviously there are a lot more colors on our new map and I still haven't given you a key,
but if you look at some of our favorite locations you may see similar shapes. Let's look back at
North Africa and the Australian outback. The population density map shows that these regions
are sparsely populated and the climate map shows these regions in bright red. In fact, check out
what happens when I show only the red places on the map. We haven't visited these places in the
course yet but using your background knowledge, can you infer a reason that North Africa and the
Australian outback aren't home to many people? Record your thoughts in the lesson guide.
If you said that these places are extremely dry or that they are deserts,
you're off to a great start! A comparison of the two maps will show that to a certain extent,
we can predict the population density of an area based on its climate.
Is it really that simple? Well, yes! Actually it is! The Köppen climate classification system
organizes the world into five major climate zones and the overwhelming majority of the
world's nearly 8 billion people lives in the temperate climate region which is characterized
by moderate temperatures and precipitation and is mostly made up of forests and grasslands.
Included in the temperate region, also called the mild mid-latitude, is much of China,
India, and the United States. The world's three most populous countries along with much of western
Europe. If human environment interaction is as big of a part of the human experience as these
maps suggest, we should take a look at the climate regions around the world and get to know them.
You learned in a previous lesson that latitude is one of the factors that determines climate,
so let's start from the equator and work our way toward the poles. You saw this map before
when we focused on North Africa. It shows arid, or extremely dry regions, the Sahara Desert in
Africa, the Middle East, the Australian outback, and the Mojave Desert in America's southwest.
Arid regions receive scarce amounts of rainfall each year and are mostly deserts and steps.
At similar latitudes are the tropical wet regions which are blue.
This region is warm, if not downright hot, most of the year because it's also close to the equator.
Rainforests such as those found in South America,
Africa, and Indonesia are a distinguishing feature of the tropics but they're also home to savannas,
or grasslands, which are common to sub-Saharan Africa, Brazil, India, and southeast Asia.
For the most part, rain forests aren't very populated with the exception of Indonesia,
the fourth largest country in the world with over 270 million people living almost exclusively in
a jungle climate. But here in Jakarta they have carved out enough room for over 10 million people.
The continental climate region is also called the
cold mid-latitude region and features a relatively dry climate with warm summers
and cold winters. The land is often marked by forests and taigas filled with millions of
trees. The continental climate region includes eastern Europe, Russia, Canada, and Alaska.
The fifth and final climate region is even less friendly to humans. The polar climate region lacks
warm summers, has little or no vegetation, and consists of tundra and ice caps. It's flat out
cold! Freezing! I mean sub-zero temperatures. Simply put, if there's anywhere on earth you
don't want to be this is probably it. The land in the polar climate region includes Antarctica and
parts of Russia and Canada located inside the arctic circle. Let's refer back to your lesson
guide. Of the five climate regions, which do you live in and which would you like to visit?
So what creates these climate regions? Well we've already covered part of this
so let's do a quick review. You probably remember from a previous lesson that the greenhouse effect
is the natural process of the sun's warming of the surface of the earth. You probably remember too
that the rotation of the earth and its revolution around the sun and the tilt of its axis causes the
seasons and makes different parts of the planet warmer than others. The sun's heat is distributed
around the globe by convection, wind patterns, and ocean currents and the warmth from the sun helps
create precipitation. All of those contribute to the climate of any given location on earth.
A location's proximity to water is also a big factor.
Water heats and cools more slowly than land masses so coastal regions will stay cooler in the summer
and warmer in the winter creating a lower range of temperature changes. A great example is California
where the entire western border of the state is formed by the Pacific Ocean. But think also about
the Mediterranean Sea and its surrounding nations, those such as Italy and Greece.
The final important factor in the climate of a location is elevation, or altitude, which you may
remember is distance above sea level. As elevation increases, atmospheric pressure will decrease
causing cooler temperatures. That's why it's cooler when you travel to the mountains.
Let's investigate what happens at different altitudes in the Himalayan mountain range
between south and east Asia. The diagram shows us that at this latitude, lower elevation areas
closer to the coasts have dense forests that receive a lot of rain and have warm temperatures.
Then, as elevation increases, cooler and cooler temperatures occur until we reach
the eternal snows where thrill seekers attempt to scale the roof of the world.
Or consider the climatological differences between Denver and Indianapolis. Many people
know Denver as the mile high city and just over a thousand miles away is Indianapolis, Indiana.
These two cities are at almost the same latitude, but elevation is a different matter. While Denver
sits more than 5,000 feet above sea level in the rocky mountains which we can see in the distance,
Indianapolis is just about 900 feet above sea level without a mountain in sight.
For this reason, Denver is a semi-arid cool climate with low humidity but lots of sunshine
whereas Indianapolis has a hot humid continental climate experiencing all four distinct seasons.
As we wrap up today's lesson on world climate regions,
think about where you live. What features of the land contribute to its climate
and what makes the climate of your hometown unique even from other places with a similar elevation
and latitude? These questions are a few more you can ask to help the world around you come
alive. Stay curious, ask questions, and until next time keep exploring!