🥔 How do we Classify Climates? Crash Course Geography #13

Key Takeaways

i'm pretty sure every cuisine in the world has embraced the potato from this simple root vegetable we get latkes gnocchi sachi papas poutine potato chips and ooh those creamy crisp potato grata with butter and cheese and a sprinkle of salt on top i'm sorry what were we talking about the potato has many claims to fame around the world from the devastating irish potato famine of the 1840s to the salty magnificence of french fries but this humble tuber originated neither in ireland nor france it was domesticated the process of adapting plants and animals for human use about seven thousand to nine thousand years ago near lake titicaca now on the border of bolivia and peru in the central andean highlands where it's known as mama jotha the mother of growth so as geographers we ask why were potatoes domesticated here and not anywhere else the story involves the ideal conditions needed for growing potatoes how climates change across space and the ingenuity of the andean farmers so today we're going to go bananas about potatoes i'm ali zay carrere and this is crash course geography [Music] worldwide the potato is one of the most calorically important food crops along with corn wheat and rice it's the cornerstone of food security for millions of people like in 2019 alone we produce 371 million tons of potatoes worldwide which is like 96 pounds of potatoes per person today the top producers of potatoes are china india ukraine russia and the us but potatoes are still integral to their south american homeland somewhere between 2 000 and 4 000 varieties of potatoes are grown along the length of the andes mountain chain different crops need different temperatures precipitation and soil conditions to thrive which brings us to an important distinction we need to get to the root of our potato story weather and climate are not the same thing weather is what's going on in the atmosphere at any given time and place today it's dry and sunny but tomorrow it may be cloudy and rainy just like my mood can change if i eat fresh hot french fries or cold soggy ones weather happens in the short term and is difficult to predict but climate is a region's average weather over many years which is much more predictable and based on trends so we don't know what the weather will be like in new york city on january 20th 2025 but we do know that it's usually chilly because new york city has a cold winter climate it's like what former president of the american meteorological society dr j marshall shepard famously probably said weather is your mood climate is your personality and my personality is a proud potato fan even though we've all had disappointing fries before just like there are endless human personalities based on our dna and how we grow up all the possible combinations of temperature precipitation wind and ocean currents give us a variety of global climates and all of those processes begin with patterns of insulation or incoming solar radiation across the globe for example mountains have complex climate patterns or the somewhat predictable variation in climate these mountain climate patterns come from the way insulation and temperature change as we go higher in elevation or the height of a point on earth's surface above a reference like sea level in fact no matter where we are on earth for every 1 000 meters we go up in elevation the air temperature decreases by 6.5 degrees celsius on average which is the normal lapse rate if you've ever hiked or driven up from the base of a mountain you've probably felt the air get chilly or brought extra layers to handle the cold temperatures the normal lapse rate has big implications for latin america's physical geography especially near the equator as we climb the andes mountains from sea level we can define our major climate zones based on elevation that have dramatic changes in plant life at the foot of the mountain is tierra caliente or hot country a low land zone of broadleaf evergreen tropical rainforest the warmth and humidity here allow extensive tall trees and a dense year-round leaf canopy to develop at about 900 meters we begin to see mild temperate conditions and deciduous forests in the tierra templada then as we continue our climb at about 1800 meters temperate conditions get chillier colder temperatures and coniferous forests mark the tierra fria as we move higher each zone gets smaller and at 3 600 meters we reach the windswept tierra elada or frost country in the lower reaches of this zone pine forests transition to alpine meadows and grasslands and mark the tree line the upper limit of where trees grow further up around 4 600 meters we see a shift from grasses to hearty lichens and mosses and beyond here we encounter the snow line or the elevation where winter snow doesn't melt in the summer this is the zone of perpetual snow that makes up the snow caps on mountains the final zone has very little plant or animal life parts of latin america use this terminology to describe mountain climate patterns but different vertical zones and geographic terms exist around the world each mountain also has unique attributes like its slope or total elevation which create different ecosystems in these zones the process of paying attention to geographic conditions like mountain climate patterns and using them to answer questions like why were potatoes domesticated in the andes mountains and not anywhere else is called geo-literacy a geoliterate person understands that the world works as a set of physical biological and social systems and that processes within these systems connect places to each other we can use these observations to interact with our environment and create particular outcomes and even though geoliteracy might be a modern term engaging with the world with a geoliterate lens is something people have been doing for thousands of years like seven to nine thousand years ago andy and farmers observed how a mountain was made of spaces with different climates and ecological niches which is where certain plants can thrive but not others and they passed this knowledge down over generations using their geographical understanding to select plots of land even today farmers all over the world need to think through all the ingredients for weather and climate to plant crops and we have all sorts of technology to help them track air pressure precipitation levels and more but ancient indian farmers didn't have these same tools let's go to the thought bubble the andean foothills and mountains are used to grow lots of crops like tomatoes beans and maize but the diversity of potatoes is a source of pride and a cultural symbol of traditional andean agriculture food systems history community and identity historically we think one way time was measured here was by how long it took to cook a pot of potatoes even today potato seeds can be gifted to young couples setting up a household and farmers in the high andes measure land based on the area a family needs to grow their supply of potatoes over the years farmers realized that when they plant their crops could make a difference between a good harvest and a poor one for example areas in what's now southern peru are prone to periods of drought as modern geographers we know that typically there are cold water currents along the peruvian coast which help bring rain to the andean highlands but some years there's a pooling of warm water along the peruvian coast which can bring drought until the ocean currents change again without the aid of satellites or an understanding of ocean currents andean farmers began to notice that if the stars especially the pleiades stars in the taurus constellation were hidden by water vapor in the atmosphere and hard to see around the winter solstice in late june it indicated an el nino year which is linked to reduced rainfall several months later so they'd plant their potatoes earlier to take advantage of whatever rain that fell if they could see the stars clearly they knew they'd get enough water to plant the potatoes a little later basically andy and farmers were geographers who observed the relationship between clouds in the atmosphere and rainfall patterns later in the season which in turn helped people survive in the andes for centuries thanks thoughtbubble anyway that people observe atmospheric conditions find patterns and make decisions based on those patterns is geography in action nowadays scientists can observe and predict climate phenomena on a global scale from ocean current patterns like el nino and the southern oscillation to what latitudes different plants like potatoes can grow at we can categorize climate patterns in a lot of different ways like using temperature and wind patterns but those can be hard to see and something like vegetation growth is much more obvious in general natural vegetation starts with a tropical rainforest at the equator and transitions into ice and snow and sparse vegetation as we get to the poles sort of mirroring the mountain climate pattern we talked about before this visible connection between vegetation and climate helped climatologist and botanist vladimir koppen devise a classification system in the early 1900s called the coppin system it's still widely used today with many improvements by many people and with many terms that reference a type of climate and type of natural vegetation like the tundra or the rain forest specifically the coppen system divides the world into six major climate categories using the visible vegetation as a guide koppen came up with precise definitions for each climate region based on average monthly temperature average monthly precipitation and total annual rainfall the first four categories are based on moisture and temperature characteristics and they're usually labeled with capital letters like a represents tropical climates which are known for having high temperatures and receiving a lot of rain and e represents polar climates which tend to be cold and dry then the last two categories are based on moisture and elevation instead of temperature like h represents the highland climates in the world's mountainous regions like where our original andean farmers grew potatoes then within each of these big categories there are subcategories marked with additional letters to break climate ups into even more precise groups so let's use potatoes as our example they thrive in cold weather so if we look at a coppin climate classification map of south america it makes sense that they thrive in the andes in the west along the andes there are bands of h which means highlands and bwk which says the area is arid desert and cold the transition out of those desert highlands is bsk which says the area is arid has a step climate and is cold those are some ideal potato growing conditions if we overlay a full coppin climate classification map with a map of everywhere potatoes are grown we see that potatoes are really hearty because there's a lot of overlap with different climates we know that many species of potato were domesticated by andean farmers but we also know that plants are adaptable those farmers used their geoliteracy to grow more plentiful crops but also to begin breeding plants to tolerate different temperatures the andean empires flourished because of food security from crops like potatoes and thanks to global trade and the hardiness of potato species today potatoes are grown in over 100 countries from india in the tropics to finland close to the arctic circle from hot and cold regions to dry and wet regions and all climate combinations in between humans have adapted to the natural environments around us and used our growing geo-literacy to thrive but increasingly the earth's environments are also impacted by our choices in future episodes we'll look at how and why maps of global climates vegetation soils and ecosystems are changing and our response to those changes and we'll hit the ground running in the next episode when we discuss how these themes relate to climate change many maps and borders represent modern geopolitical divisions that have often been decided without the consultation permission or recognition of the land's original inhabitants many geographical place names also don't reflect the indigenous or aboriginal people's languages so we at crash course want to acknowledge these people's traditional and ongoing relationship with that land and all the physical and human geographical elements of it we encourage you to learn more about the history of the place you call home through resources like nativeland.ca and by engaging with your local indigenous and aboriginal nations through the websites and resources they provide thanks for watching this episode of crash course geography which is filmed at the team sandoval pierce studio and was made with the help of all these nice people if you want to help keep crash course free for everyone forever you can join our community on patreon