New heat record

The Lut Desert in Iran is the hottest place in the world. This is the result of satellite data that measure the temperature on the earth’s surface over a wide area. In 2005, it was over 70 degrees Celsius in Lut in the Iranian highlands. This replaced Al Aziziyah in Libya as the record holder. A temperature of 58 degrees was recorded there in 1922.

It is the largest desert in Iran: Lut is located in the Iranian highlands in the east of the country. The fact that the place hardly gets a drop of water is due to the dry trade winds and the surrounding mountains that shield the rain. The Lut Desert is so dry and hot that not even bacteria can live here. Between 2003 and 2009, the highest temperatures on earth were measured there. In 2005, it was even 70.7 degrees Celsius directly on the ground.

Not only in Iran, but also elsewhere the temperatures are like in a well-heated oven. According to satellite measurements, 69.3 degrees have already been reached in the Queensland bush in Australia, and 66.8 degrees in the “Flaming Mountains” in northwest China.

Until now, Al Aziziyah in Libya on the edge of the Sahara was considered the hottest place in the world. A weather station there measured a temperature of 58 degrees in 1922. However, until now the records were very incomplete. This is because the weather stations are widely scattered and leave out many places. Only modern satellite measurement makes it possible to record the temperature without gaps and to measure it where it is highest: directly on the ground.

At the cold pole of the earth

Never before has a lower temperature been measured on Earth: On 21 July 1983, the thermometer at the Russian research station Vostok dropped to an almost unimaginable minus 89.2 degrees Celsius. Normally, temperatures here fluctuate between minus 30 and minus 60 degrees. The Vostok station is located in Antarctica at an altitude of just under 3,500 metres, close to the “Pole of Inaccessibility”: this is the place in Antarctica that is furthest from the sea and therefore extremely difficult to reach. The Vostok station has also had a nickname since the icy July of 1983: The “Cold Pole of the Earth”.

What are climate zones?

In the morning cloudy to partly cloudy with showers. In the afternoon the sun will shine, with temperatures between 16 and 22 degrees”, this may be the weather forecast for southern Germany. The forecast is interesting for us because the weather is constantly changing. It is different with the climate, because that remains. Climate means the average weather of a region over a longer period of time. For example, the climate at the equator is hot and humid all year round. At the North Pole, on the other hand, temperatures are freezing and there is little precipitation. Between the equator and the poles, there are areas where it can be very changeable, just like here. But why is it that the climate on Earth is so different?

The sun’s radiation is not equally strong everywhere on earth. How intensively it heats the earth depends on the angle of the sun’s radiation and thus on the latitude. Because the sun is almost vertical all year round near the equator, the earth is heated very strongly here. Towards the poles, the sun’s rays strike at an increasingly shallow angle: The same solar energy is distributed over an ever larger area. Therefore, the greater the distance to the equator, the cooler it becomes. This creates regions with different climates, the climate zones.

According to the strength of the sun’s rays, four different climate zones can be divided on the mainland of the earth: The tropics around the equator, the subtropics (from the Latin word “sub” for “under”) between the 23rd and the 40th parallel, the temperate zone of our latitudes and the polar regions around the North and South Poles. Like belts, these climate zones run around the earth in an east-west direction.

However, the climate does not only depend on the latitude, other influences also play a role. For example, there is snow on Mount Kilimanjaro even though it is in the tropics. The fact that its summit is icy is due to the fact that the temperature drops with increasing altitude. Mountain climates are therefore always cooler than lower-lying areas.

The distance to the sea also affects the climate: Water can store solar heat longer than land. It also warms up more slowly than the land. As a result, seawater acts as a buffer for temperatures. The climate is therefore mild near the coast. Inland, this heat balance is missing and the climate is continental, with temperatures fluctuating much more than in the maritime climate near the sea.

From rainforest to tundra – vegetation zones

Trees and deciduous forests can thrive well in cool and humid areas. Where it is particularly hot and dry, on the other hand, hardly anything grows: deserts form there. Only plants that are as well adapted to this extreme climate as cacti have a chance to survive here.

Plants depend on the climate: where which species are at home is determined above all by the temperature and the amount of precipitation. That is why there are many different regions on earth with specific plant communities: the vegetation zones. Because the type of vegetation depends on the climate, these vegetation zones, similar to the climate zones, run roughly parallel to the equator.

The typical vegetation zones include, for example, the rainforest in the ever-humid tropics. With increasing distance from the equator, the grasslands of the savannahs, on which trees and shrubs also thrive in isolated cases, are the typical vegetation. Towards the poles, the subtropics follow with deserts and semi-deserts, the special plants of the alternating and ever-humid subtropics, the deciduous and mixed forests of the temperate latitudes and the coniferous forests of the cold temperate zone. In the areas around the poles, only particularly hardy shrubs, mosses and lichens grow. This last vegetation zone before the polar desert of ice is called tundra

The boundaries of the vegetation zones are not always easy to recognise; their transitions are fluid. This is also due to the fact that humans have an influence on the plant world: By clearing forests, cultivating the land and building cities, they change the original vegetation. If you want to describe which plants are actually growing at the moment, you also talk about ecozones.

Subtropics

In summer, many sun-seekers are drawn to Italy, Spain or Greece because it is warm and dry there. All these Mediterranean countries belong to the subtropical climate zone, which lies between the tropics and the temperate zone. But the subtropics do not only include the entire Mediterranean region with its hot, dry summers and mild, humid winters. As in the tropics, the subtropics also have different climates with their own plant communities in different places.

In the dry subtropics near the equator it hardly rains. Because of the great aridity, almost nothing grows here except extremely adapted plants like cacti. This zone is home to large deserts such as the Sahara in North Africa, the Atacama in northern Chile or the Namib on the west coast of Africa.

Towards the poles it gets wetter: the Mediterranean is quite dry in summer, but in winter areas of rain move in from the west. However, there is hardly any frost even in the cold season. This subtropical winter rain climate on the western sides of the continents is not only found on the Mediterranean, by the way. California and South Africa also have a Mediterranean climate. The vegetation has adapted to the climatic situation. Typical plants are those that can retain their foliage even in winter. Their leathery leaves can store water well and draw on it in times of drought. These hard-leaved plants include, for example, rosemary and olive trees.

In the ever-humid subtropics, on the other hand, rain falls all year round. It rains particularly heavily in summer. Then monsoon winds blow in from the east, which have absorbed a lot of moisture over the sea and rain it back down over the land. Because of the high rainfall, the plants grow very luxuriantly there: the subtropical humid forests resemble tropical rainforests. Originally, such humid forests existed in the south-east of the USA, in East Asia or in northern Argentina. However, large parts of these forests have been cleared to make room for agriculture.

Polar Regions – Arctic and Antarctic

The largest ice surfaces on earth are around the North Pole and the South Pole. Because of their special location, the polar regions receive very little sunlight and solar heat, and the summers are particularly short there. That is why it is always extremely cold there – temperatures of up to minus 70 degrees Celsius prevail throughout the year. The cold has allowed huge masses of ice to form in the polar regions.

The Arctic ice around the North Pole covers a large part of the Arctic Ocean in winter. It then covers an area of several million square kilometres. For the most part, this is a layer of ice that floats on the sea. In addition, the Arctic ice covers the northern areas of Europe, Asia and North America.

In contrast, the South Pole is located on a continent, Antarctica. Antarctica is the coldest place on earth. Its land mass is almost completely buried under a shell of ice and snow up to 4 kilometres thick. Almost three quarters of the fresh water on Earth is stored in this ice.

Humans, animals and plants have adapted to life in the “eternal ice”. Polar bears or reindeer, for example, protect themselves against the cold with a layer of fat and thick fur. Only a few people inhabit the Antarctic, the Arctic is somewhat more densely populated. The best-known inhabitants of the Arctic are the Inuit in North America and Greenland, but there are also the Lapps in northern Scandinavia and indigenous peoples in northern Siberia. In the past, they lived there as nomads and moved around with dog sleds. Today they use snowmobiles and many of them live in cities.

Hardly anything grows in the ice deserts around the poles because of the great cold. The ground between the polar regions and the cold temperate zone is permanently frozen to great depths. This ground is therefore also called permafrost after the Latin word “permanere” for “to last”. It only thaws slightly a few months a year. Then particularly hardy plants such as mosses, lichens or dwarf shrubs can grow on it. This region around the polar regions is also called subpolar tundra.

The polar regions are the coldest areas on earth. It is also here that it is apparent that the Earth is heating up: for some years now, researchers have been observing that the ice masses of the Arctic and Antarctic are melting. The consequences of this warming cannot yet be precisely estimated. But it is already clear that many habitats are threatened by the melting of the poles.

Big-eared Rabbits

When the antelope rabbit sweats, it does so mainly through its ears, which are a good 20 cm long. These giant spoons give off excess heat to the environment. And this is vital for the rodent, because the antelope hare lives in the hot, dry deserts of Arizona and Mexico.

It can grow up to 70 cm long and weigh almost seven kilograms. This makes the antelope hare one of the largest of all lagomorphs. A quarter of its body surface is covered by its long spoons. They are not only good for hearing, but also for survival. By emitting heat through them, the hare protects itself against the heat in the deserts of North America. Nevertheless, the long-eared hare prefers to spend its days in the shade of rocks and sparse desert plants. Only in the evening does it go in search of food. In the twilight, it munches on grasses and herbs, leaves and cacti.

Far away – in Canada and Alaska – lives a close relative: the snowshoe hare. It has much smaller ears than the antelope hare so that it does not lose heat. On the other hand, it lives on a large foot: its legs are long and densely hairy on the soles, which makes them look like snowshoes. With them, he cannot sink in the deep snow of the north. He also adapts the colour of his fur to the seasons and the climate. In summer, the snowshoe hare wears dark brown, in winter white. This is how it camouflages itself from its numerous enemies: the fox, the wolf, the coyote and various birds of prey.

The snowshoe hare and the antelope hare have another trick against extinction in common and completely independent of the climate: like other hare species, they are very fertile and reproduce quite quickly.

The Saguaro National Park in Arizona

We call them Armleuchter cacti in German because they look like giant candlesticks. Where they thrive, in the southwest of the USA and in Mexico, they are called Saguaros. Growing several metres high, these impressive cacti are the emblem of Saguaro National Park in the southwest of the United States of America. The national park is part of the Sonora Desert, which stretches from Arizona far into Mexico. In this hot, dry desert climate, only plants that can withstand extreme heat and drought thrive. Besides various types of cacti, they include pines or junipers and even flowers such as lupines and gold poppies. The animal world has also adapted. The antelope hare, various bird species, rattlesnakes, lizards and tortoises are at home in this amazingly species-rich desert.