What are the benefits of population growth

Education, nutrition, the environment : What are the consequences of population growth - and how it can be combated

Ten billion people could live on earth by 2050, and by 2100 it could even be almost eleven billion. Population growth poses huge challenges for mankind. Many questions have to be solved: How should so many people be fed at all, what consequences does growth have for the environment - and how can population growth be slowed down at all?

Since Tuesday, thousands of experts have been discussing how dramatic the situation is and what possible solutions are available at the World Population Conference in Nairobi. You have a lot to talk about.

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Right at the top of the agenda: The situation of women worldwide. When the United Nations adopted its 17 sustainability goals four years ago, ending discrimination against women was one of them, number 5 on the list.

First and foremost, gender equality is a fundamental human right, wrote UN Women, the department of the World Organization for Gender Issues and Women's Empowerment.

The main topic of education: How does it help to reduce the number of births?

But it is also "the greatest opportunity to meet some of the most pressing challenges of our time". So a key to solving economic crises, poor health care, wars and climate change?

Education is generally seen as a key factor: the longer girls can go to school, the more often they have access to paid work and thus opportunities to support themselves and their families.

The more the number of their births falls - with the result that women are healthier themselves and can take better care of their children. These effects can be seen from practically all available data.

The latest figures from the UN organization in September are still dramatic: worldwide, ten million boys of primary school age do not attend school. There are as many as 15 million of the girls.

According to this, women currently spend three times more time in unpaid work than men, and almost two thirds of all married or cohabiting women cannot decide on contraception themselves.

Equality advances more than just the female half of the world

Education is part of a larger problem - that of “women's rights”. In the majority of countries around the world, women are prevented to a greater or lesser extent from having paid work, getting loans, concluding contracts or even traveling freely and opening a bank account. That was the result of a study by the World Bank that appeared this year.

However, the experts are also making progress, most of them in sub-Saharan Africa. In the past ten years, laws to protect against sexual violence have been passed and women have been given the opportunity to take out loans. A third of the countries that made the most progress, often from a low level, overcame the exclusion of women from certain occupations.

The fact that more equality actually promotes the world more than just the female half of the world can also be seen in the figures: a few years ago, the UN food organization FAO expected 20 to 30 percent higher agricultural yields if women in developing countries go to school as often as men are allowed to visit, get capital and own the land they are working. In fact, they only own a fifth, even though they produce up to 80 percent of the food.

The major topic of nutrition: How are ten billion people cared for?

In addition to education, nutrition is one of the major topics. To feed the ten billion people who will live on earth by 2050, around twice as much food must be produced as today. This is shown by calculations by the United Nations. The question is how (and whether) this can be achieved. And above all, how this can be achieved without additional overexploitation of nature, i.e. without converting nature conservation areas into arable land.

As daunting as the task is, the positive news is that it has been solved before. Sixty years ago, agriculture produced around 200 kilograms of grain for each of the then three billion people. Today it is 400 kilograms - that is not only a doubling, but almost a quadrupling, because today over 7.5 billion people live on earth.

Read more about population growth:

This "green revolution" only succeeded because the yield of the most important food crops per square meter of arable land increased immensely, especially wheat, maize and rice.

Nitrogen fertilization, the protection of plants against pests with the help of pesticides and, first and foremost, the constant breeding development of the high-performance varieties - mind you without those methods that are generally referred to as “genetic engineering” - all contributed to this.

Changes in the genome increase the size of the grains of wheat

These have only been on the market since the end of the 1990s - and still hardly play a role in food production with only 190 million hectares of genetically modified plants on the total of 1,600 million hectares of cultivation area worldwide.

Nevertheless, changes in the genetic make-up are due to the fact that the grains of wheat have become larger, stronger stalks carry heavier corn cobs and rice has become more resistant to fungal attack. These mutations are also caused by techniques that change genes: chemical substances (mutagens) and radiation.

In the process, many plants with unsuitable properties emerged - uncontrolled and by chance - but also those that breeders then used to produce today's high-performance varieties. One example is the “Kurzstroh” wheat: The shorter stalks due to a mutation were more stable and were able to hold the larger ears better even in strong winds.

Researchers are expecting a lot from the CRISPR gene scissors

In addition, breeders also used a genetic trick to increase yield, the heterosis effect. Accordingly, the direct offspring, the hybrids, of two different pure-breeding varieties are particularly vigorous, more resistant and, above all, more productive. Hybrid breeding plays an important role, especially with maize and rye, but also broccoli and tomatoes.

Even the next “Green Revolution” will not do without progress in breeding, ie interventions in the genetic make-up. So the only question is which methods are suitable. By means of “genome editing”, such as the gene scissors method CRISPR / Cas9, the TALEN or the RTDS technology, changes can now be brought about in specific areas in the genome - instead of the entire genome and tens of thousands of genes being randomly assigned as was previously the case shoot and hope for a chance hit in the right gene.

With these changes, researchers hope that plants can get by with less water, withstand higher salt concentrations in the soil, become more resistant to diseases and pests or simply produce larger, more durable fruits - all properties that ultimately lead to higher yields.

Some of these “edited” plants are still in development, others are already on the market, at least in the USA, where a mushroom made more durable by genome editing has been approved. In Europe, genome-modified plant varieties are considered genetically modified and have to be tested in a complex and expensive manner, which makes their development in this country uneconomical.

Cultivation methods also have to change

As important as breeding is for the next green revolution, whether using classic gene-modifying methods or genome editing, it alone will not be able to achieve the necessary increases in yield. It will be just as important to improve the cultivation methods for many other food crops besides corn, rice and wheat, such as cassava.

New fertilization methods must also be developed, both to support the plants, but also to maintain fertile soils in the long term and sustainably. If the bacteria that fertilize soy or certain types of maize with nitrogen from the air could also be used in wheat and rice, this would not only have an impact on yields. One could save the production of nitrogen fertilizers, which uses a lot of fossil, climate-damaging energy sources, in the future.

Major topic: the environment: How does population growth contribute to environmental degradation?

It is undisputed that population growth has massive environmental impacts and is driving climate change and the extinction of species. Because for every additional person you need a piece of land on which your food grows. And this land then lacks nature and biodiversity. Every additional citizen on earth needs energy, even if it is only for cooking - and thus heats up the climate a little further.

In fact, humans have now destroyed 85 percent of all wetlands worldwide. 99 percent of all reefs are considered endangered. “And between 2010 and 2015 alone, 32 million hectares of forest were cleared, which is almost the size of Germany,” says Christof Schenck, Managing Director of the Frankfurt Zoological Society (ZGF), describing the effects that human lifestyles have on nature Has.

As a result, not only does the home of many species disappear, but these species often die out.

These effects can be clearly observed in Ethiopia: Whereas 22.1 million people lived there in 1960, there are now 111 million. In these six decades, Ethiopia has already lost 80 percent of its forests. And that can have dramatic consequences not only for nature conservation. Species like the Ethiopian wolf live there at altitudes between 1500 and 4400 meters in an area the size of the Saarland, which is only found there.

The forests in the lower regions of Bale National Park soak up the rainfall like a giant sponge. "That's why 40 rivers have their source there, three of which flow into the neighboring country Somalia and supply twelve million people there with water," explains Christof Schenck.

Example Ethiopia: The rivers are drying up

However, population growth could soon cut these lifelines. While a few thousand people lived in Bale National Park in 1986, today there are around 30,000 who cut firewood for their stoves in the forests. 300,000 head of cattle graze in the park and not only serve as suppliers of milk and meat, but are also a kind of social security. "If people need money for medical treatment or other unforeseen events, they simply sell a cattle," says Schenck, whose organization fights for nature conservation in the Bale Mountains National Park.

The resistance, however, is great, the fight can hardly be won: the forest is still being cleared for pasture areas and fields. If the trees are not protected, the rain will wash away the soil. A karst landscape emerges quickly. But then the farmers in Bale National Park can no longer find any firewood. An even bigger humanitarian catastrophe threatens: Because the rivers dry up, the water supply of twelve million people in neighboring Somalia is threatened.

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