The geological age of our planet is approximately 4.5 billion years. During this period, the Earth has changed dramatically. The composition of the atmosphere, the mass of the planet itself, the climate - at the beginning of existence, everything was completely different. The red-hot ball very slowly became what we used to see it now. Collided tectonic plates, forming all new mountain systems. On a gradually cooling planet, seas and oceans formed. Continents appeared and disappeared, their shape and size changed. The earth began to rotate more slowly. The first plants appeared, and then life itself. Accordingly, over the past billions of years on the planet, dramatic changes have taken place in moisture circulation, heat circulation and atmospheric composition. Climate change has occurred throughout the Earth’s existence.
The era of the Holocene
Holocene - part of the Quaternary period of the Cenozoic era. In other words, this is an era that began about 12 thousand years ago and continues to the present moment. The Holocene began with the end of the ice age, and since then, climate change on the planet has gone towards global warming. This era is often called interglacial, since there have been several ice ages in the entire climate history of the planet.
The last global cooling occurred about 110 thousand years ago. About 14 thousand years ago, warming began, gradually covering the entire planet. The glaciers that covered most of the Northern Hemisphere at that time began to melt and collapse. Naturally, all this did not happen overnight. For a very long period, the planet was shaken by strong temperature fluctuations, glaciers either advancing or retreating again. All this influenced the level of the oceans.
Holocene periods
During numerous studies, scientists decided to divide the Holocene into several time periods depending on the climate. Approximately 12-10 thousand years ago, ice sheets disappeared, and postglacial period came. In Europe, the tundra began to disappear, it was replaced by birch, pine and taiga forests. This time is commonly called the arctic and subarctic period.
Then came the boreal era. Taiga pushed the tundra farther north. Broad-leaved forests appeared in southern Europe. At this time, the climate was mostly cool and dry.
About 6 thousand years ago, the Atlantic era began, during which the air became warm and humid, much warmer than the modern one. This time period is considered the climatic optimum of the entire Holocene. Half of Iceland was covered with birch forests. Europe abounded with a wide variety of thermophilic plants. At the same time, the extent of temperate forests was much further north. Dark coniferous forests grew on the shores of the Barents Sea, and the taiga reached Cape Chelyuskin. On the site of modern Sahara there was a savannah, and the water level in Lake Chad was 40 meters higher than the modern one.
Then again, climate change occurred. The cooling took about 2 thousand years. This period of time is called subboreal. Mountain ranges in Alaska, Iceland, and the Alps have acquired glaciers. Landscape zones shifted closer to the equator.
About 2.5 thousand years ago, the last period of the modern Holocene, the Sub-Atlantic, began. The climate of this era has become cooler and wetter. Peat bogs began to appear, the tundra gradually began to perch on the forests, and forests on the steppes. Around the 14th century, a cooling of the climate began, leading to the small ice age, which lasted until the middle of the 19th century. At this time, glacier invasions were recorded in the mountains of Northern Europe, Iceland, Alaska and the Andes. At different points on the globe, the climate did not change synchronously. The reasons for the onset of the small ice age are still unknown. According to scientists, the climate could change due to increased volcanic eruptions and a decrease in the concentration of carbon dioxide in the atmosphere.
Beginning of meteorological observations
The first meteorological stations appeared at the end of the 18th century. Since that time, constant observations of climatic fluctuations have been carried out. It can be reliably argued that the warming that began after the small ice age continues to the present.
Since the end of the 19th century, an increase in the average global temperature of the planet has been recorded. In the middle of the 20th century there was a slight cooling, which did not affect the climate as a whole. Since the mid 70's it has become warmer again. According to scientists, over the past century, the global temperature of the Earth has increased by 0.74 degrees. The highest growth of this indicator was recorded in the last 30 years.
Climate change invariably affects the state of the oceans. An increase in global temperature leads to the expansion of water, and hence to an increase in its level. There are also changes in the distribution of precipitation, which, in turn, can affect the flow of rivers and glaciers.
According to observations, the level of the oceans over the past 100 years has increased by 5 cm. Scientists attribute the climate warming to an increase in carbon dioxide concentration and a significant increase in the greenhouse effect.
Climate-forming factors
Scientists have conducted many archaeological research and concluded that the planet’s climate has changed dramatically more than once. Many hypotheses have been put forward in this regard. According to one opinion, if the distance between the Earth and the Sun remains the same, as well as the speed of rotation of the planet and the angle of the axis, then the climate will remain stable.
External factors of climate change:
- A change in solar radiation leads to the transformation of solar radiation fluxes.
- The movements of tectonic plates affect the orography of the land, as well as the level of the ocean and its circulation.
- The gas composition of the atmosphere, in particular the concentration of methane and carbon dioxide.
- Changing the tilt of the Earth's axis of rotation
- Change in the parameters of the planet’s orbit in relation to the Sun.
- Earth and space disasters.
Human activities and their impact on climate
The reasons for climate change are connected, among other things, with the fact that humanity has interfered with nature throughout its existence. Deforestation, plowing of land, land reclamation , etc., lead to transformations of humid and wind regimes.
When people make changes to the surrounding nature, draining swamps, creating artificial ponds, cutting down forests or planting new ones, building cities, etc., the microclimate changes. The forest greatly affects the wind regime, which determines how the snow cover will fall, how much the soil will freeze.
Green spaces in cities reduce the effect of solar radiation, increase air humidity, reduce the difference in temperature in the daytime and evening, reduce dustiness of the air.
If people cut down forests on the hills, then in the future this leads to the erosion of the soil. Also, reducing the number of trees lowers global temperature. However, this means an increase in the concentration of carbon dioxide in the air, which is not only not absorbed by trees, but also additionally released during the decomposition of wood. All this compensates for the decrease in global temperature and leads to its increase.
Industry and its impact on climate
The causes of climate change lie not only in general warming, but also in the activities of mankind. People have increased the concentration in the air of such substances as carbon dioxide, nitrous oxide, methane, tropospheric ozone, chlorofluorocarbons. All this ultimately leads to an increase in the greenhouse effect, and the consequences may be irreversible.
Every day, industrial enterprises emit a lot of dangerous gases into the air. Everywhere transport is used that pollutes the atmosphere with its exhausts. A lot of carbon dioxide is formed during the burning of oil and coal. Even agriculture causes considerable damage to the atmosphere. About 14% of all greenhouse gas emissions are in this area. This includes plowing the fields, and burning waste, burning the savannah, manure, fertilizers, animal husbandry, etc. The greenhouse effect helps maintain the temperature balance on the planet, but human activity enhances this effect several times. And this can lead to disaster.
Why should we be wary of climate change?
97% of the world's climatologists are sure that in the last 100 years, everything has been greatly transformed. And the main problem of climate change is anthropogenic activity. It is impossible to reliably say how serious this situation is, but there are many reasons for concern:
- Have to redraw the map of the world. The fact is that if the eternal glaciers of the Arctic and Antarctica melt, accounting for approximately 2% of the world's water reserves, the ocean level will rise by 150 meters. According to rough forecasts of scientists, the Arctic will be free of ice in the summer of 2050. Many coastal cities will suffer, a number of island states will disappear completely.
- The threat of global food shortages. Already, the world's population is more than seven billion people. In the next 50 years, it is expected that the population will increase by another two billion. With the current trend towards an increase in life expectancy and a decrease in infant mortality in 2050, food will require 70% more than the current figures. By then, many regions could be flooded. An increase in temperature will turn part of the plain into a desert. Crops will be in danger.
- The melting of the Arctic and Antarctica will lead to global emissions of carbon dioxide and methane. Under the eternal ice is a huge amount of greenhouse gases. Having escaped into the atmosphere, they will repeatedly strengthen the greenhouse effect, which will lead to disastrous consequences for all of humanity.
- Ocean oxidation. About a third of the carbon dioxide settles in the ocean, but supersaturation with this gas will lead to the oxidation of water. The industrial revolution has already led to an increase in oxidation by 30%.
- Mass extinction of species. Of course, extinction is a natural process of evolution. But lately, too many animals and plants are dying, and the reason for this is the activity of mankind.
- Weather disasters. Global warming leads to disasters. Droughts, floods, hurricanes, earthquakes, tsunamis - everything is becoming more and more intense. Now extreme weather conditions are killing up to 106 thousand people a year, and this figure will only grow.
- The inevitability of war. Droughts and floods will turn entire regions into unsuitable for life, which means that people will seek the opportunity to survive. The war for resources will begin.
- Change in ocean currents. The main "heater" of Europe is the Gulf Stream - a warm current flowing along the Atlantic Ocean. Already, this current is sinking to the bottom and is changing its direction. If the process continues, then Europe will be under a layer of snow. There will be big weather problems around the globe.
- Climate change is already costing billions. It is not known how much this figure can grow if everything continues.
- Earth Hacking. No one can predict how much the planet will change as a result of global warming. Scientists are developing ways to prevent symptoms. One of them is the release of large volumes of sulfur into the atmosphere. This will simulate the effect of a huge volcanic eruption and lead to a cooling of the planet due to blockage of sunlight. However, it is not known how this system will actually affect and whether humanity will only make worse.
UN Convention
The governments of most countries on the planet are seriously worried about the consequences of climate change. More than 20 years ago, an international treaty was created - the United Nations Framework Convention on Climate Change. It considers all possible measures to prevent global warming. Now the convention has been ratified by 186 countries, including Russia. All participants are differentiated into 3 groups: industrialized countries, countries with economic development and developing countries.
The UN Convention on Climate Change is fighting to reduce the growth of greenhouse gases in the atmosphere and further stabilize performance. This can be achieved either by increasing the flow of greenhouse gases from the atmosphere, or by reducing their emissions. The first option requires a large number of young forests that will absorb carbon dioxide from the atmosphere, and the second option will be achieved if you reduce the consumption of fossil fuels. All ratified countries agree that global climate change is taking place. The UN is ready to do everything possible to mitigate the impending impact.
Many countries participating in the convention have concluded that joint projects and programs will be most effective. Currently, there are more than 150 such projects. Officially, 9 similar programs work in Russia, and unofficially - more than 40.
At the end of 1997, the Convention on Climate Change signed the Kyoto Protocol, which stated that countries with economies in transition are committed to reducing greenhouse gas emissions. The protocol has been ratified by 35 countries.
Our country also took part in the implementation of this protocol. Climate change in Russia has doubled the number of natural disasters. Even taking into account that boreal forests are located on the territory of the state, they cannot cope with all greenhouse gas emissions. Forest ecosystems should be improved and expanded, and large-scale measures to reduce emissions from industrial enterprises should be carried out.
Forecasts of the effects of global warming
The essence of climate change in the last century is global warming. According to the worst forecasts, the further irrational activity of mankind can raise the Earth's temperature by 11 degrees. Climate change will be irreversible. The planet will slow down, many species of animals and plants will die. Sea level will rise so much that many islands and most of the coastal areas will be flooded. The Gulf Stream will change course, leading to a new small ice age in Europe. Widespread cataclysms, floods, tornadoes, hurricanes, droughts, tsunamis, etc. will begin. Melting ice in the Arctic and Antarctica will begin.
For humanity, the consequences will be catastrophic. In addition to the need to survive in conditions of strong natural anomalies, people will have many other problems. In particular, the number of cardiovascular diseases, respiratory diseases, psychological disorders will increase, outbreaks of epidemics will begin. There will be an acute shortage of food and drinking water.
What to do?
To avoid the effects of climate change, we first need to reduce the level of greenhouse gases in the atmosphere. Humanity should switch to new sources of energy, which should be low-carb and renewable. Sooner or later, the world community will face this question sharply, since the currently used resource - mineral fuel - is non-renewable. Someday, scientists will have to create new, more efficient technologies.
It is also necessary to reduce the level of carbon dioxide in the atmosphere, and only restoration of forest areas can help with this.
It is required to apply maximum efforts to stabilize the global temperature on Earth. But even if this does not succeed, mankind should try to achieve minimal consequences of global warming.