How will the climate change by the end of the 21st century?

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How will the climate change by the end of the 21st century?
How will the climate change by the end of the 21st century?
Anonim

Many people still continue to argue whether global warming is a myth or a real phenomenon. However, in the scientific world, a consensus has actually been reached on this matter. Yes - climate change is happening right before our eyes. Yes - it is mostly caused by human activity. And no - it will not carry it through: this process will potentially affect every person on the planet.

global warming

Warming to combat warming

So far, 97% of climate change experts agree that the observed climate change is largely human-induced. The path to this consensus (3% is not enough for complete unanimity, but the number of scientific articles denying this consensus is negligible) was long.

For example, some of the most prominent developing countries in greenhouse gas emissions accused Western scientists of their research being political. As if the results they obtained were fabricated and specifically aimed at forcing the leadership of some promising economies to make decisions that would slow down these economies in any case.

Recently, however, even the planet's biggest "polluter" and the main skeptic of environmental policy - China - unexpectedly agreed on the need to start a serious fight against climate change and signed an agreement to reduce greenhouse gas emissions by 2030. It is very likely that China will be followed in this historic decision by other countries whose leaders are not yet serious about this problem.

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But why, after all, is there so much hype around global warming, and what does it actually threaten us with?

The secret conspiracy that could

First, there are a few things to clarify. There are two different terms - "global warming" and "climate change". The first, the most popularized in the media, is a gradual increase in the average air temperature near the planet's surface over almost the entire history of observations.

This is just a special case of the second, much broader concept - “climate change”. It includes not only warming, but also a whole range of climatic phenomena, such as melting glaciers, rising mean sea levels, decreasing ice sheets in the Arctic and Antarctic, and so on.

Now we are observing not only signs of warming, but also large-scale climate changes: ice sheets (Greenland, Antarctica) are gradually melting, the water level in the oceans is rising, the seasons of algal bloom are shifting.

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At the same time, humans, knowing how strongly climatic changes in the planet's past have been linked to CO levels2 in the atmosphere, they continue to burn huge volumes of hydrocarbons (oil, coal), thereby replenishing the atmosphere with carbon dioxide. Excess CO2 accumulates for a long time in the upper atmosphere, gives off part of the heat to the oceans, they heat up - and now we are on the verge of global climate change.

It would be convenient to attribute what is happening to the natural dynamics of the climate. But in official science, almost no one adheres to this point of view.First, if the Sun was to blame for climate change or, say, fluctuations in the Earth's orbit or axis of rotation, then warming should have been observed in the upper atmosphere - after all, the solar radiation reaching the Earth should have increased. However, this is not observed - the stratosphere, on the contrary, cools.

Secondly, the anthropogenic impact, that is, the human factor, can be identified by comparing the historical levels of carbon dioxide in the atmosphere with what we are seeing now. Since our planet is constantly going through the ice and interglacial periods, geologists have long known what the CO levels were.2 in "cold" times, and what - in "warm".

In particular, it was found that in the last ice ages, this figure averaged about 180 parts per million by volume, and in interglacial (now we are in the interglacial) - 280 particles. However, modern measurements show that this number has already reached 385 particles. This means that over 200 years of rapid industrial development, we have emitted as much carbon dioxide into the atmosphere as nature has emitted in 20 thousand years!

Given how closely this indicator is linked to climate change, it is not surprising that we are living in an era of massive climate change. It should be added that, according to the natural dynamics of the climate, it should now, on the contrary, be getting colder - this is demonstrated both by the data on the Earth's orbit and by the data on cyclical climate changes, according to which we are moving towards a new ice age.

In other words, if global warming is a secret conspiracy of some "world behind the scenes" to slow down the development of some countries, then its participants have overdone it a little.

Climatic crossroads

So, the warming of the climate is leaving more and more obvious traces. Right before our eyes, temperature anomalies are becoming more frequent (remember at least the recent snowfall in the northeastern United States), and some settlements are submerged under water for 10 months a year.

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Not surprising: according to the latest report of the United Nations Intergovernmental Panel on Climate Change (IPCC), which has been working on this problem since 1988, over the past century, the world ocean level has risen by about 19 centimeters, and the average temperature on the Earth's surface by about 0.8 degrees Celsius …

In 2007, the IPCC modeled (and subsequently augmented) four scenarios for how climate change would evolve up to 2100. Of course, it would be easier to construct one most probable scenario, but it is impossible, since forecasting is required taking into account factors for which data will appear only in the future.

The experts from the IPCC chose the forecasted amount of carbon dioxide emissions into the atmosphere as the key one. In other words, each of the scenarios is based on some assessment of how seriously the international community can take the reduction of CO emissions.2 and what results he will be able to achieve in this field.

Let's consider two of the most interesting options - conditionally pessimistic (RCP8.5), where people stopped paying attention to the problems of climate change altogether, and the opposite - conditionally optimistic (RCP2.6), where people managed to cope with their energy appetite.

Everything is very bad

The pessimistic scenario, dubbed RCP8.5, suggests a situation in which humanity, even by 2100, was unable to get rid of inefficient energy based on burning hydrocarbons, and refused to fight global warming. The number of people on the planet has reached 12 billion, most of the developing countries have already achieved relative prosperity - and, of course, everyone wants to live in normal conditions, have electricity in the house, personal transport and other benefits.

To provide energy to 12 billion demanding earthlings, unprecedented costs will be required.Technological progress in this scenario has slowed down greatly, so a breakthrough in energy efficiency cannot be expected, as well as a complete replacement with renewable sources. Mankind is forced to turn to the "classic" - coal, the rate of combustion of which, according to the gloomy realities of RCP8.5, will increase 10 times by the end of the 21st century.

Since the fight against warming in this world is out of the question, this scenario has the most alarming predictions: the ocean level with such carelessness of the authorities by the end of the century should rise by 52-98 centimeters, and the temperature near the Earth's surface by an average of about 4 degrees.

What will this mean for us? To determine the possible consequences, the site geology.com turns out to be very visual, where in a special application you can see which coastal regions and cities will submerge with a certain rise in the water level in the oceans.

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The rise by one meter, as predicted by the RCP8.5 scenario, will result in a multitude of cataclysms. Water will fill the streets of Amsterdam, Shanghai and even London (the Thames will overflow its banks as the rivers become much wider). It is better not to mention the fate of the most vulnerable island states in this context. As with all other scenarios, humans will inevitably have to either build defensive walls around cities or throw them down after a flood.

An increase in air temperature by 4 degrees will mean a global ecological catastrophe. Due to such significant changes on the planet, biodiversity will be drastically reduced - according to some estimates, a quarter of all currently existing species may die.

In the meantime, humanity will suffer a humanitarian catastrophe - increased droughts, lack of food and especially drinking water will lead to the emergence of a completely new phenomenon - climate refugees who will be forced to move to more favorable regions for living. All this will undoubtedly lead to an unprecedented rise in political tension, and potentially to wars.

But even that is not all. The rise in water levels per meter is just the beginning of a belated response from the global climate system to the amount of greenhouse gases that humans, according to the RCP8.5 scenario, have released into the atmosphere.

As a result of any unforeseen circumstances that aggravate the situation (for example, the release of huge volumes of greenhouse gas methane due to the melting of permafrost in Siberia), the water by 2100 may rise by 1.5 meters, and after a few centuries - already by 7 meters. In this case, cities such as New York and Mumbai will have to be moved or abandoned.

Everything is pretty good

The optimistic scenario, called RCP2.6, may seem a bit idealistic. However, modeling has shown that it is “technically” possible. The experts from the IPCC agree with this.

RCP2.6 looks at a world in which absolutely all states have realized the seriousness of the threat posed by global warming. Uniting in the fulfillment of a common task - to prevent the average temperature at the Earth's surface from exceeding 2 degrees Celsius - mankind is actively developing technologies in the field of energy and spreading them at lightning speed even among the poorest countries.

To achieve this goal, it will be necessary to stop the growth of greenhouse gas emissions by 2020, and during the 21st century to reduce this figure by at least 70%.

To reduce the damage to the world economy from such radical measures, not only alternative types of energy, such as solar panels and wind generators, will be developed, but also methods of increasing energy efficiency, that is, minimizing the consequences for the environment and other costs with maximum return. This will allow getting the same (or more) amount of energy from classical energy carriers (hydrocarbons) while reducing both costs and greenhouse gas emissions.

In this context, experts emphasize that it is not necessary to completely abandon oil and coal. A key role here should be played by the active introduction of a highly promising anti-warming technology called BECCS (bioenergy using carbon capture and storage technology). The main attraction of BECCS is that it leads to so-called negative CO emissions.2, allowing you to permanently remove carbon dioxide produced at various enterprises from the Earth's atmosphere.

According to many researchers, excluding BECCS from the climate warming equation will make it impossible to fulfill the RCP2.6 scenario, that is, limiting the temperature rise by 2100 to 2 degrees and below. Of course, the comprehensive implementation of this technology has its pitfalls (a huge amount of biomass is required), but these problems, scientists say, can be solved.

Payback for prosperity

Thus, the global cohesion of the entire international community and the active development of technologies in the field of energy will make it possible to avoid the catastrophic consequences of global warming. However, this does not mean a happy ending at all. People will still not be able to live the way they used to, since the consequences of the industrial revolution will continue to affect the climate due to the inertia of the climate system itself.

Alas, even with the most optimistic development of events described by the RCP2.6 scenario, the ocean level by 2100 may rise by at least 28 centimeters (maximum - by 61), and the temperature near the earth's surface may rise by about 1 degree Celsius.

NASA data that show anomalies (changes) in temperature from 1885 to 2013. Each frame (year) refers to a five-year period before it. That is, let's say the opening frame from 1885 shows anomalies compared to the period 1880-1884. Red indicates temperature changes upward, blue - downward.

This means that any development of events will cause significant damage to biological diversity - the extinction of many species is possible. The climate in arid regions will become even drier and the risk of forest fires will increase. This, in turn, will exacerbate the inevitable shortage of drinking water, which many experts call the “gold of the 21st century” (there will be no more fresh water even without climate warming - simply because the world's population is growing too quickly).

Floods will also become much more frequent. It is unlikely that the flooding of some coastal settlements, including large cities, will be avoided. Some vulnerable but developed countries - for example, the Netherlands and Denmark - are likely to have time to build flood defenses, as they have not only the financial ability to do this, but also the corresponding many years of experience.

However, others will not be able to do this, at least independently and quickly. For example, Bangladesh - one of the poorest countries in the world - due to its geographical location is one of the most vulnerable to global warming countries. Even a slight rise in ocean water levels will cause the largest rivers in Bangladesh to overflow their banks. This threatens to flood the 10 millionth capital of the state - Dhaka.

Small island states are the most vulnerable in the context of global warming. At the moment, the first-ever project to move the administrative center of the island to the mainland due to global warming is already being developed - perhaps it will become an example for everyone else. In the future, countries like Kiribati and the Maldives could disappear from the face of the Earth forever.

But that's not all: experts from the IPCC in every report emphasize that warming after 2100, whatever the outcome of the fight against climate change, will not stop.Experts agree that the ocean level, even if the requirements of RCP2.6 are met, may rise by one meter by the end of the XXIII century.

Replay the climate

One can look at global warming from a different angle and ask the question: can some countries not only lose, but also gain from climate change?

While politicians in the international arena are engaged in "replaying" each other, in the future, countries such as Russia and Canada will have a chance to replay the climate itself. And without doing practically anything for this.

The fact is that warming is most actively manifested in the Northern Hemisphere, especially in the Arctic and Siberia. The climate there is changing more rapidly than in most other regions. However, in conditions of permafrost and unsuitable conditions for living, warming becomes more a blessing for a person than a misfortune.

According to a study by an international group of scientists, including researchers from the Russian Academy of Sciences, South Siberia is turning over time into an increasingly attractive region for farming. The northern border of crops such as grain, potatoes and silage corn can be moved 50-70 km every ten years.

Areas closer to the southern borders of Siberia, meanwhile, may become suitable for growing sunflowers, melons, pumpkins, berries and ordinary corn. In a dry climate, this will require irrigation, but the favorable position of the largest Siberian rivers - the Ob, Yenisei and Lena - will make it easy to solve this problem, scientists say.

Also, due to warming, the Northern Sea Route will throw off the ice shackles, which, of course, will greatly benefit the country's economy.

Do not forget that Russia is among the leaders in terms of fresh water reserves, and Lake Baikal contains 1/5 of all drinking water in the world. Global warming will increase access to water resources in Russia and Canada, which will not only ensure food security for these countries in the 21st century, but can also become a very lucrative source of export trade. And this, in turn, will help to solve the problem of the aggravating shortage of drinking water in other countries.

There is, of course, a downside. Floods will become more frequent - Russia already faced this factor in 2013. Infrastructure designed for permafrost could also be seriously affected. Methane explosions, which are likely to accelerate global warming and sprinkle with mesmerizing holes in Siberia, also do little good for nearby settlements.

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In general, there are still more advantages, the climate in Russia will become softer. In this context, one can recall the ancient theory - geographical determinism, according to which the mentality of a people is rigidly determined by the geographical (and other natural) conditions in which it lives. If global warming is not stopped, we are likely to have the first-ever full test of this theory.

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