How is moisture distributed on the surface of the earth? Weather and climate

Video tutorial 2: Atmosphere structure, meaning, study

Lecture: Atmosphere. Composition, structure, circulation. Distribution of heat and moisture on Earth. Weather and climate

Atmosphere

Atmosphere can be called an all-pervading shell. Her gaseous state allows you to fill microscopic holes in the soil, water is dissolved in water, animals, plants and humans cannot exist without air.

The conventional thickness of the shell is 1500 km. Its upper boundaries dissolve in space and are not clearly marked. The atmospheric pressure at sea level at 0 ° C is 760 mm. rt. Art. The gas shell consists of 78% nitrogen, 21% oxygen, 1% other gases (ozone, helium, water vapor, carbon dioxide). The density of the air shell changes with increasing altitude: the higher you go, the thinner the air. This is why climbers may experience oxygen deprivation. The earth's surface itself has the highest density.

Composition, structure, circulation

The shell contains layers:

Troposphere, 8-20 km thick. Moreover, the thickness of the troposphere at the poles is less than at the equator. About 80% of the total air mass is concentrated in this small layer. The troposphere tends to heat up from the surface of the earth, so its temperature is higher near the earth itself. With a rise of 1 km. the temperature of the air shell decreases by 6°C. In the troposphere, active movement of air masses occurs in the vertical and horizontal directions. It is this shell that is the weather “factory”. Cyclones and anticyclones form in it, westerly and easterly winds. It contains all the water vapor that condenses and is shed by rain or snow. This layer of the atmosphere contains impurities: smoke, ash, dust, soot, everything we breathe. The layer bordering the stratosphere is called the tropopause. This is where the temperature drop ends.

Approximate boundaries stratosphere 11-55 km. Up to 25 km. Minor changes in temperature occur, and above it it begins to rise from -56 ° C to 0 ° C at an altitude of 40 km. For another 15 kilometers the temperature does not change; this layer is called the stratopause. The stratosphere contains ozone (O3), a protective barrier for the Earth. Thanks to the presence of the ozone layer, harmful ultraviolet rays do not penetrate the surface of the earth. Lately Anthropogenic activities have led to the destruction of this layer and the formation of “ozone holes.” Scientists claim that the cause of the “holes” is the increased concentration free radicals and freon. Under the influence solar radiation gas molecules are destroyed, this process is accompanied by a glow (northern lights).

From 50-55 km. the next layer begins - mesosphere, which rises to 80-90 km. In this layer the temperature decreases, at an altitude of 80 km it is -90°C. In the troposphere, the temperature again rises to several hundred degrees. Thermosphere extends up to 800 km. Upper limits exosphere are not detected, since the gas dissipates and partially goes into outer space.

Heat and moisture

The distribution of solar heat on the planet depends on the latitude of the place. The equator and tropics receive more solar energy, since the angle of incidence of solar rays is about 90°. The closer to the poles, the angle of incidence of the rays decreases, and accordingly the amount of heat also decreases. sun rays, passing through the air shell, do not heat it. Only when it hits the ground, solar heat is absorbed by the surface of the earth, and then the air is heated from the underlying surface. The same thing happens in the ocean, except that the water heats up more slowly than the land and cools down more slowly. Therefore, the proximity of seas and oceans influences the formation of climate. In summer, sea air brings us coolness and precipitation, in winter it warms, since the surface of the ocean has not yet spent its heat accumulated over the summer, and the earth's surface has quickly cooled. Marine air masses are formed above the surface of the water, therefore, they are saturated with water vapor. Moving over land, air masses lose moisture, bringing precipitation. Continental air masses form above the surface of the earth, as a rule, they are dry. The presence of continental air masses in summer brings hot weather, in winter - clear frosty.

Weather and climate

Weather– the state of the troposphere in a given place for a certain period of time.

Climate– long-term weather regime characteristic of a given area.

The weather can change during the day. Climate is a more constant characteristic. Each physical-geographical region is characterized by certain type climate. The climate is formed as a result of the interaction and mutual influence of several factors: the latitude of the place, the prevailing air masses, the topography of the underlying surface, the presence of underwater currents, the presence or absence of water bodies.

On the earth's surface there are belts of low and high atmospheric pressure. Equatorial and temperate zones low pressure, at the poles and in the tropics the pressure is high. Air masses move from the area high pressure to the low area. But since our Earth rotates, these directions deviate, in the northern hemisphere to the right, in the southern hemisphere to the left. Trade winds blow from the tropical zone to the equator, westerly winds blow from the tropical zone to the temperate zone, and polar eastern winds blow from the poles to the temperate zone. But in each zone, land areas alternate with water areas. Depending on whether the air mass has formed over land or ocean, it may bring heavy rain or a clear, sunny surface. The amount of moisture in air masses is affected by the topography of the underlying surface. Over flat areas, moisture-saturated air masses pass without obstacles. But if there are mountains on the way, it’s hard humid air cannot move through the mountains, and is forced to lose part, or even all, of the moisture on the mountain slope. East Coast Africa has a mountainous surface (the Drakensberg Mountains). Air masses forming over Indian Ocean, are saturated with moisture, but they lose all the water on the coast, and a hot, dry wind comes inland. That's why most South Africa occupied by deserts.

The role of air currents in climate formation

1. Remember from the 6th grade geography course what conditions are necessary for education atmospheric precipitation. Can cold air contain a lot of moisture? What kind of air is called saturated with water vapor?
2. Using the atlas map, determine where on Earth there is a lot of precipitation and where there is little.
3. What is atmospheric pressure? How does it affect the weather in your area?
4. How do wind direction and air masses affect the weather in your area?

The climates of individual places differ not only in temperature, but also in precipitation, which is distributed very unevenly on the earth's surface. Some areas suffer from excess moisture, others from lack. Areas located along the Northern and Southern Tropics, where temperatures are high and the need for precipitation is especially great, receive especially little precipitation. Vast areas of the globe with large number heat, not used in agriculture due to lack of moisture. How can we explain the uneven distribution of precipitation? Main reason- air movement, which depends on atmospheric pressure belts and the rotation of the Earth around its axis.

Distribution of atmospheric pressure belts on Earth. On the Earth's surface there are three belts with a predominance of low pressure and four belts with a predominance of high pressure (Fig. 16). Atmospheric pressure belts are formed as a result of the uneven distribution of solar heat on the earth's surface, as well as the influence of the deflecting force of the Earth's rotation around its axis.

Rice. 16. Distribution of atmospheric pressure belts (High pressure belt - high pressure belt, LP - low pressure belt) and the main types of air masses

Air moves not only horizontally, but also in the cortical direction. Strongly heated air near the equator expands, becomes lighter and therefore rises, i.e. upward movement air. In this regard, low pressure forms at the Earth's surface near the equator. At the poles due to low temperatures the air cools, becomes heavier and sinks, i.e. downward air movement occurs (Fig. 17). In this regard, the pressure at the Earth's surface near the poles is high.

In the upper troposphere, on the contrary, above equatorial region, where upward air movement predominates, pressure is high (although lower than at the Earth's surface), and low above the poles. Air is constantly moving from areas high blood pressure in the low area. Therefore, the air rising above the equator spreads towards the poles. But due to the rotation of the Earth around its axis, the moving air gradually deviates to the east and does not reach the poles. As it cools, it becomes heavier and sinks at about 30° N. and Yu. w. At the same time, it forms areas of high pressure in both hemispheres. Over the thirtieth latitude, as well as over the poles, downward air currents predominate.

Now let’s look at the relationship between pressure belts and precipitation. Thus, near the equator, in a low-pressure zone, constantly heated air contains a lot of moisture. As it rises, it cools and becomes saturated. Therefore, many clouds form in the equator region and heavy precipitation occurs (see Fig. 17). A lot of precipitation also falls in other areas of the earth's surface where pressure is low.

Rice. 17. Diagram of air movement in the troposphere, revealing the formation of atmospheric pressure belts and associated precipitation

In high pressure belts, downward air currents predominate. Cold air, as it descends, contains little moisture. When lowered, it contracts and heats up, due to which it moves away from the state of saturation and becomes drier. Therefore, in areas of high pressure over the tropics and near the poles, little precipitation falls (see Fig. 17). The distribution of precipitation also depends on geographical latitude. The less solar heat, the less precipitation.

Constant winds. The formation of constant winds, i.e. always blowing in the same direction, depends on the belts of high and low pressure. Since in equatorial belt Low pressure prevails, and high pressure near the thirtieth latitude, then at the Earth's surface the winds blow from high pressure belts to the equator. Such winds are called trade winds. Under the influence of the Earth's rotation around its axis, trade winds deviate in the Northern Hemisphere to the right, i.e., to the west, and blow from northeast to southwest, and in the Southern Hemisphere - to the left and are directed from southeast to northwest (Fig. 18 ).

IN temperate latitudes Western winds predominate. Let's look at how they are formed. From tropical zones high pressure winds blow not only towards the equator, but also towards the poles, since at 65° N. and Yu. w. low pressure prevails. However, due to the rotation of the Earth, they gradually deviate to the east (in the Northern Hemisphere - to the right, and in the Southern Hemisphere - to the left) and create an air coil from west to east (see Fig. 18). The movement of atmospheric pressure belts over the seasons, either north or south, causes the movement of areas of constant winds.

Rice. 18. Diagram of air currents near the Earth’s surface (on the right - under the condition of Earth rotation). Compare figures 17 and 18, indicate the pressure zones in the figure and explain the formation of trade winds and westerly winds in temperate latitudes

Air masses. We often see how hot, sunny weather in summer suddenly gives way to cool and rainy weather, and in winter, after thaws, severe frosts set in. What explains the rapid change in weather? The main reason for such changes is the movement of air masses. If air remains over the same area for a long time, it acquires certain properties: temperature, humidity, dust. Large volumes of troposphere air with homogeneous properties are called air mass. Depending on the place of formation of air masses, four types are distinguished: equatorial air mass, or equatorial air - (EV), tropical - (TV), temperate - (HC), Arctic and Antarctic - (AV). Their properties depend on the territories over which they are formed (see Fig. 16).

Figure 19 shows the areas of formation of air masses when the Sun is at noon at the zenith above the equator, i.e. on the equinoxes. Due to the movement of the zenithal position of the Sun, both atmospheric pressure belts and air masses move north or south.

Rice. 19. Scheme of movement of air masses by season and the formation of climatic zones

As air masses move, they retain their properties for a long time and therefore determine the weather of the places where they arrive.

The role of air currents in climate formation. Air masses, being constantly in motion, transfer heat (cold) and moisture (dryness) from one latitude to another, from the oceans to the continents and from the continents to the oceans. Due to the movement of air masses, heat and moisture are redistributed on the Earth's surface. If there were no air currents, then it would be much hotter at the equator, and much colder at the poles, than it actually is. Thus, climate depends not only on the height of the Sun above the horizon, but also on the movement of air masses - on air currents.

1. Why is there a lot of precipitation near the equator, but little in tropical areas? What is the relationship between atmospheric pressure belts and precipitation?
2. Name constant winds above the earth's surface and explain their formation.
3. What is an air mass?
4. What is the role of air currents in the distribution of heat and moisture on the Earth's surface?

Basic concepts, processes, patterns and their consequences

Biosphere is the totality of all living organisms on Earth. A holistic doctrine of the biosphere was developed by the Russian scientist V.I. Vernadsky. The main elements of the biosphere include: vegetation (flora), fauna (fauna) and soil. Endemics- plants or animals that are found on the same continent. Currently in the biosphere species composition Animals predominate almost three times over plants, but the biomass of plants is 1000 times greater than the biomass of animals. In the ocean, the biomass of fauna exceeds the biomass of flora. The biomass of land as a whole is 200 times greater than that of the oceans.

Biocenosis- a community of interconnected living organisms inhabiting an area of ​​the earth's surface with homogeneous conditions.

Altitudinal zone- a natural change of landscapes in the mountains, due to altitude above sea level. Altitudinal zones correspond to natural zones on the plain, with the exception of the alpine and subalpine meadows located between the belts coniferous forests and tundra. The change of natural zones in the mountains occurs as if we were moving along the plain from the equator to the poles. The natural zone at the base of the mountain corresponds to the latitudinal natural zone in which the mountain system is located. Quantity altitude zones in the mountains depends on the height of the mountain system and its geographical location. The closer to the equator the mountain system is located and the higher the altitude, the more altitude zones and types of landscapes will be represented.

Geographical envelope- a special shell of the Earth, within which the lithosphere, hydrosphere, lower layers of the atmosphere and the biosphere, or living matter, touch, penetrate each other and interact. The development of the geographical envelope has its own patterns:

• integrity - the unity of the shell due to the close relationship of its components; manifests itself in the fact that a change in one component of nature inevitably causes a change in all the others;
• cyclicality (rhythmicity) - recurrence of similar phenomena over time, there are rhythms of different durations(9-day, annual, periods of mountain building, etc.);
• cycles of matter and energy - consists in the continuous movement and transformation of all components of the shell from one state to another, which determines the continuous development of the geographical shell;
• zoning and altitudinal zone- a natural change in natural components and natural complexes from the equator to the poles, from the foot to the top of the mountains.

Reserve- specially protected by law natural area, completely excluded from economic activity for the protection and study of typical or unique natural complexes.

Landscape- a territory with a natural combination of relief, climate, land waters, soils, biocenoses that interact and form an inextricable system.

National Park- a vast territory that combines the protection of picturesque landscapes with their intensive use for tourism purposes.

Soil- top thin layer earth's crust, inhabited by organisms, containing organic matter and having fertility - the ability to provide plants with what they need nutrients and moisture. The formation of a particular type of soil depends on many factors. Release into soil organic matter and moisture determines the humus content, which ensures soil fertility. Largest quantity humus is contained in chernozems. Depending on the mechanical composition (the ratio of mineral particles of sand and clay of different sizes), soils are divided into clayey, loamy, sandy loam and sandy.

Natural area- a territory with similar temperatures and humidity values, naturally extending in the latitudinal direction (on the plains) across the surface of the Earth. On continents, some natural zones have special names, for example, the steppe zone in South America is called a pump, and in North America- prairies. Wet zone equatorial forests in South America - the selva, the savannah zone occupying the Orinoco Lowland - the Llanos, the Brazilian and Guiana Plateau - the Campos.

Natural complex- an area of ​​the earth's surface with homogeneous natural conditions, which are determined by the peculiarities of origin and historical development, geographical location, operating within its boundaries modern processes. In a natural complex, all components are interconnected. Natural complexes vary in size: geographic envelope, continent, ocean, natural area, ravine, lake ; their formation occurs over a long period of time.

Natural areas of the world

Natural area	Climate type	Vegetation	Animal world	Soils
Arctic (Antarctic) deserts	Arctic (Antarctic) maritime and continental	Mosses, lichens, algae. Most of it is occupied by glaciers	Polar bear, penguin (in Antarctica), gulls, guillemots, etc.	Arctic deserts
Tundra	Subarctic	Shrubs, mosses, lichens	Reindeer, lemming, arctic fox, wolf, etc.
Forest-tundra	Subarctic	Birch, spruce, larch, shrubs, sedges	Elk, brown bear, squirrel, white hare, tundra animals, etc.	Tundra-gley, podzolized
Taiga		Pine, fir, spruce, larch, birch, aspen	Elk, brown bear, lynx, sable, chipmunk, squirrel, mountain hare, etc.	Podzolic, permafrost-taiga
Mixed forests	Moderate continental, continental	Spruce, pine, oak, maple, linden, aspen	Elk, squirrel, beaver, mink, marten, etc.	Sod-podzolic
Broadleaf forests	Moderate continental, monsoonal	Oak, beech, hornbeam, elm, maple, linden; on Far East- cork oak, velvet wood	Roe deer, marten, deer, etc.	Gray and brown forest
Forest-steppe	Moderately continental, continental, sharply continental	Pine, larch, birch, aspen, oak, linden, maple with areas of mixed-grass steppes	Wolf, fox, hare, rodents	Gray forest, podzolized chernozems
Steppe	Moderate continental, continental, sharply continental, subtropical continental	Fescue, fescue, thin-legged grass, forbs	Gophers, marmots, voles, corsac foxes, steppe wolves, etc.	Typical chernozems, chestnut, chernozem-like
Semi-deserts and deserts temperate zone	Continental, sharply continental	Wormwood, grasses, subshrubs, feather grass, etc.	Rodents, saiga, goitered gazelle, corsac fox	Light chestnut, solonetz, gray-brown
Mediterranean evergreen forests and bushes	Mediterranean subtropical	Cork oak, olive, laurel, cypress, etc.	Rabbit, mountain goats, rams	Brown
Wet sub tropical forests	Subtropical monsoon	Laurel, camellias, bamboo, oak, beech, hornbeam, cypress	Himalayan bear, panda, leopard, macaques, gibbons	Red soils, yellow soils
Tropical deserts	Tropical continental	Solyanka, wormwood, acacia, succulents	Antelope, camel, reptiles	Sandy, sierozems, gray-brown
Savannah		Baobab, umbrella acacias, mimosa, palm trees, spurge, aloe	Antelope, zebra, buffalo, rhinoceros, giraffe, elephant, crocodile, hippopotamus, lion	Red-brown
Monsoon forests	Subequatorial, tropical	Teak, eucalyptus, evergreen species	Elephant, buffalo, monkeys, etc.	Red soils, yellow soils
Wet equatorial forests	Equatorial	Palm trees, hevea, legumes, vines, banana	Okapi, tapir, monkeys, forest pig, leopard, pygmy hippopotamus	Red-yellow ferralite

Endemics of the continents

Mainland	Plants	Animals
Africa	Baobab, ebony, velvichia	Secretary Bird, striped zebra, giraffe, tsetse fly, okapi, marabou bird
Australia	Eucalyptus (500 species), bottle tree, casuarinas	Echidna, platypus, kangaroo, wombat, koala, marsupial mole, marsupial devil, lyrebird, dingo
Antarctica	—	Adelie Penguin
North America	Sequoia	Skunk, bison, coyote, grizzly bear
South America	Hevea, cocoa tree, cinchona, ceiba	Armadillo, anteater, sloth, anaconda, condor, hummingbird, chinchilla, llama, tapir
Eurasia	Myrtle, ginseng, lemongrass, ginkgo	Bison, orangutan, Ussuri tiger, panda

The most large deserts peace

Precipitation on our planet is distributed extremely unevenly. In some areas, it rains every day and so much moisture reaches the surface of the Earth that rivers remain full all year round, and tropical forests rise in tiers, covering sunlight. But you can also find places on the planet where for several years in a row not a drop of rain falls from the sky, the dried-up beds of temporary water streams crack under the rays of the scorching Sun, and meager plants can only reach deep layers thanks to long roots. groundwater. What is the reason for such injustice? Precipitation distribution on globe depends on how many clouds containing moisture form over a given area or how many of them the wind can bring. Air temperature is very important, because intensive evaporation of moisture occurs precisely at high temperature. Moisture evaporates, rises and a certain height clouds form.

Air temperature decreases from the equator to the poles, therefore, the amount of precipitation is maximum at equatorial latitudes and decreases towards the poles. However, on land, the distribution of precipitation depends on a number of additional factors.

There is a lot of precipitation over coastal areas, and as you move away from the oceans, their amount decreases. There is more precipitation on the windy slopes of mountain ranges and significantly less on the leeward ones. For example, on Atlantic coast In Norway, Bergen receives 1,730 mm of precipitation per year, while Oslo (beyond the ridge) receives only 560 mm. Low mountains also affect the distribution of precipitation - on the western slope of the Urals, in Ufa, an average of 600 mm of precipitation falls, and on the eastern slope, in Chelyabinsk, 370 mm.

The distribution of precipitation is also influenced by the currents of the World Ocean. Over the areas near which they pass warm currents, the amount of precipitation increases, as from warm water masses the air heats up, it rises and clouds with sufficient water content form. Over areas near which cold currents pass, the air cools and sinks, clouds do not form, and much less precipitation falls.

The greatest amount of precipitation falls in the Amazon basin, off the coast of the Gulf of Guinea and in Indonesia. In some areas of Indonesia, their maximum values ​​reach 7000 mm per year. In India, in the foothills of the Himalayas at an altitude of about 1300 m above sea level, there is the most rainy place on Earth - Cherrapunji (25.3° N and 91.8° E), where an average of more than 11,000 mm of precipitation falls per year. Such an abundance of moisture brings to these places the humid summer southwest monsoon, which rises along the steep slopes of the mountains, cools and sheds heavy rain.

If the ocean floor is expanding at the suture zone of a mid-ocean ridge, this means that either the Earth's surface is increasing or there are areas where the oceanic crust is disappearing and sinking into the asthenosphere. Such areas, called subduction zones, have actually been found in a belt bordering the Pacific Ocean and in a discontinuous strip extending from Southeast Asia to the Mediterranean. All these zones are confined to deep-sea trenches encircling island arcs. Most geologists believe that on the surface of the Earth there are several rigid lithospheric plates that “float” on the asthenosphere. Plates can slide past one another, or one can sink beneath another in a subduction zone. The unified model of plate tectonics provides the best explanation for the distribution of large geological structures and zones of tectonic activity, as well as the change relative position continents.Seismic zones. Mid-ocean ridges and subduction zones are belts of frequent strong earthquakes And volcanic eruptions. These areas are connected by long linear faults that can be traced across the globe. Earthquakes are confined to faults and very rarely occur in any other areas. Towards the continents, the epicenters of earthquakes are located deeper and deeper. This fact provides an explanation for the mechanism of subduction: the expanding oceanic plate plunges under the volcanic belt at an angle of approx. 45° . As it “slides,” the oceanic crust melts into magma, which flows through cracks as lava to the surface.Mountain building. Where ancient ocean basins are destroyed by subduction, continental plates collide with each other or with fragments of plates. As soon as this happens, the earth's crust is greatly compressed, a thrust is formed, and the thickness of the crust almost doubles. Due to isostasy, the folded zone experiences uplift and thus mountains are born. The belt of mountain structures of the Alpine stage of folding can be traced along the coast Pacific Ocean and in the Alpine-Himalayan zone. In these areas, numerous collisions of lithospheric plates and uplift of the territory began ca. 50 million years ago. More ancient mountain systems, such as the Appalachians, are over 250 million years old, but at present they are so destroyed and smoothed that they have lost their typical mountain appearance and turned into an almost flat surface. However, since their "roots" are embedded in the mantle and float, they have experienced repeated uplift. And yet, over time, such ancient mountains will turn into plains. Majority geological processes They go through the stages of youth, maturity and old age, but usually this cycle takes a very long time.Heat and moisture distribution. The interaction of the hydrosphere and the atmosphere controls the distribution of heat and moisture on the earth's surface. The relationship between land and sea largely determines the nature of the climate. When the land surface increases, cooling occurs. The uneven distribution of land and sea is currently a prerequisite for the development of glaciation.

The Earth's surface and atmosphere receive the most heat from the Sun, which throughout the entire existence of our planet emits thermal and light energy with almost the same intensity. The atmosphere prevents the Earth from returning this energy too quickly back into space. About 34% solar radiation lost due to reflection by clouds, 19% is absorbed by the atmosphere and only 47% reaches the earth's surface. The total influx of solar radiation to the upper boundary of the atmosphere is equal to the release of radiation from this boundary into outer space. As a result, the thermal balance of the “Earth atmosphere” system is established.

The land surface and ground air quickly heat up during the day and lose heat quite quickly at night. If there were no heat-trapping layers in the upper troposphere, the amplitude of daily temperature fluctuations could be much greater. For example, the Moon receives about the same amount of heat from the Sun as the Earth, but because the Moon has no atmosphere, its surface temperatures rise during the day to about 101

° C, and at night they drop to 153°C. The oceans, whose water temperature changes much more slowly than the temperature of the earth's surface or air, have a strong moderating effect on the climate. At night and in winter, air over the oceans cools much more slowly than over land, and if oceanic air masses move over continents, this leads to warming. Conversely, during the day and summer the sea breeze cools the land.

The distribution of moisture on the earth's surface is determined by the water cycle in nature. Every second, huge amounts of water evaporate into the atmosphere, mainly from the surface of the oceans. Moist oceanic air, sweeping over the continents, cools. The moisture then condenses and returns to earth's surface in the form of rain or snow. Partially it is stored in snow cover, rivers and lakes, and partially returns to the ocean, where evaporation occurs again. This completes the hydrological cycle.

Ocean currents are the Earth's powerful thermoregulatory mechanism. Thanks to them, uniform moderate temperature And warm waters transported to colder high-latitude regions.

Since water plays a significant role in erosion processes, it thereby affects the movements of the earth's crust. And any redistribution of masses caused by such movements under the conditions of the Earth rotating around its axis can, in turn, contribute to a change in the position of the Earth’s axis. During ice ages Sea levels are falling as water accumulates in glaciers. This, in turn, leads to the expansion of continents and increased climatic contrasts. Reduced river flows and lower sea levels prevent warm temperatures from reaching ocean currents cold regions, leading to further climate changes.