New concept may meet human resource needs of 'full Earth'
The world's human population is expected to grow from seven billion to more than 10 billion over the next two to three generations, leading to a "full Earth" scenario.
"This increase in population, coupled with rising per capita income and associated change in consumption habits, will put unprecedented stress on food, energy and water resources," said Rakesh Agrawal, professor at Purdue University in the US. "The grand challenge before us is to sustainably meet the needs of a full Earth using scarcer resources, and the sun is the key energy source to achieve this goal," said Agrawal.
He led a team which proposes a system that would use the entire solar spectrum to maximise resource production from a given land area. The concept, described in the journal Scientific Reports, works by separating and harvesting the three specific segments of the solar spectrum that are best suited to facilitate the production of food, energy and clean water.
In current practices, much of this spectrum is wasted because all of the sunlight falling on a given spot is used solely for one purpose, such as agriculture, energy production or water purification. The new approach would instead use the same land mass for all three purposes simultaneously through innovative technologies that split the spectrum into three segments and efficiently harvest sunlight.
A typical photovoltaic panel, when installed on farmland, casts a shadow and dramatically reduces plant growth and crop yield from the shadowed area. The proposed photovoltaic designs transmit photons responsible for plant growth while reflecting remaining photons in the solar spectrum to specially-designed solar cells to generate electricity and collect heat for energy recovery and water purification. "The advantage of our proposed solution is clear," Agrawal said.
"With the three-way split, the entire spectrum is judiciously used for the production of food, energy and water resources," he said. Solar spectrum splitting to maximise electric power generation and heat recovery is well known, said Muhammad Ashraful Alam, Professor at Purdue.
The proposed system could create solar-powered, self- sufficient communities - a major step towards full-Earth preparedness, Peter Bermel, an assistant professor at Purdue said. "Implementing this approach across agricultural land areas could supply extra electricity to the power grid, as well as freshwater supplies to other areas in need, thus improving global resilience," he said.
comment:- i disagree:-
Global population set to hit 9.7 billion people by 2050 despite fall in ...
https://www.theguardian.com › World › Development › Environmental sustainability
but then population will decline
Study: World Population to Stop Growing - ABC News
abcnews.go.com/Technology/story?id=98371
World population could be nearly 11 billion by 2100 -- ScienceDaily
https://www.sciencedaily.com/releases/2013/06/130613111942.htm
Very long range global population scenarios to 2300 - Demographic ...
https://www.demographic-research.org/volumes/vol28/39/28-39.pdf
by S Basten - 2013 - Cited by 17 - Related articles
May 30, 2013 - population will either decline to 2.3-2.9 billion by 2200 or increase to ... While most existing world population projections agree that we are ...What will the human population of the world be in the year 2500 ...
https://www.quora.com/What-will-the-human-population-of-the-world-be-in-the-year...
Just 500 Japanese. An empty Europe. The world dying out..
As fertility rates fall a 'birth dearth' is spreading, write Anthony Browne and Richard Reeves
Even as the six billionth human is born, it's time to forget fears about
the world being overpopulated. By the end of the next millennium, Tokyo
will be a ghost town, and Japan will be empty. The country's population
will be just 500 by the year 3000, and just one by 3500. When that
person dies, the Japanese nation will be no more.
These apocalyptic predictions aren't the rantings of a doomsday cult,
or of a maverick academic out to gain some publicity, but of the
Japanese government itself. Its Ministry of Health and Welfare reports:
'If we dare make the calculation, Japan's population will be… about 500
people by the year 3000.'
Of course, a lot of things can change in 1,000 years. But what is frightening about the forecast is that it's a mathematical certainty if Japanese women carry on having just 1.4 children each on average - and if Japan doesn't change its immigration policy. If things continue as they are, the Japanese will die out. It's just a question of when.
And so will we.
Britain is one of 61 countries that are not having enough babies to replace their populations, according to the United Nations. For a population to remain stable, women need to have 2.1 babies each on average. In the UK, women are now having just 1.7 babies. One in four women are now opting to have none at all.
In all the countries of the European Union, fertility is now so low that populations are set to decline - if they haven't already. Spanish women - having just 1.15 babies each - have the lowest fertility in the world. In some parts of Spain the average rate has dropped below one.
The European Commission says fewer babies were born last year in the EU than in any year since the Second World War.
'Obviously, the social structure is going to change dramatically in the next century,' says John Clarke, professor of geography at the University of Durham.
'We are going to become used to a world with no-child and one-child families, and with a growing proportion of older people. Siblings will become rarer and rarer.'
Clarke points out that the unprecedented 'birth dearth' is even spreading to some developing countries. Women in India now have fewer babies than American women did in the 1950s, while in China, Cuba and Thailand women are already having too few babies to replace themselves.
After centuries of population growth, and decades of apocalyptic warnings about the population bomb, most of the developed world is now facing a 'population bust'. In his landmark 1968 book, Population Bomb, Professor Paul Ehrlich warned that 'we will breed ourselves into oblivion'. Thirty years later, demographers say he is right - but not in the way he expected.
Even a few years ago predictions abounded that the exponential growth in the world's population would mean that by around 3000 there would be standing room only on the planet. One demographer predicted the impossible, claiming that in the fifth millennium humanity would outweigh the planet itself.
But the unexpectedly sharp decline in fertility around the world has forced all forecasters - including the UN - to downgrade their predictions. There are now 6 billion people in the world, and while the UN's best guess is that the global population will reach 9bn by 2050, it admits the total could peak as low as 7.5bn by 2040 before falling back.
Almost all that growth will be in Africa and Asia, outweighing sharp falls in much of the developed world. The UN predicts that by 2050, Russia's population will have declined by 25 million people, Japan's by 21m, Italy's by 16m, and Germany's and Spain's by 9m each. Britain, with a younger population and more babies, is less affected - at least initially. The UN forecasts the British population will drop by 2m by 2050 before the decline accelerates.
The most catastrophic fall will be in Estonia, which is set to lose more than a third of its population in the next 50 years.
Samuel Preston of the University of Pennsylvania reckons Europe will lose 24 per cent of its population by 2060. The UN forecasts that Europe and Japan will lose half their population by 2100.
All this is not just crystal ball gazing. The European Commission says the 'natural' populations of Germany, Greece, Italy and Sweden fell last year - with only immigration ensuring that the overall populations remained steady. The populations of all but two of the countries in central and Eastern Europe fell in 1997, with Latvia's dropping by almost 1 per cent.
Of course, longer-term projections are shaky. 'We really do have to differentiate between shorter-term projections, say up to 30 years, and the longer-term ones which by definition are highly speculative,' Clarke says.
Nonetheless, he says, there is little prospect of a dramatic change in the fertility figures. 'The main factors driving the change are changes in social attitudes towards smaller families and the decline of the extended family, and even more important, the huge change in the status of women as they enter the labour market in greater numbers. I don't see, for the foreseeable future, much chance of an increase in family size.'
The implications of the birth dearth are potentially as far-reaching as those of the population bomb. Most debate has focused on the related issue of an ageing population, and the crippling cost of providing pensions, but a falling population presents problems of its own.
Housebuilders will become as outdated as cartwrights;
property prices will fall as ghost towns proliferate.
Traffic jams and overflowing trains will be things of the past.
The environment - or what is left of it - will benefit as
fewer people pollute less.
The military may have to raise maximum ages to fill the ranks;
schools will need to be remodelled as lifelong learning centres or knocked down.
Businesses brought up on expanding markets will have to get used to a shrinking customer base. Workforces will shrink, eradicating unemployment and creating labour shortages. In just 10 years, the population of working age will be contracting by 1 per cent a year in Italy, Germany and Japan.
Countries hooked on permanent economic growth will have to adapt to permanent recession, as their populations - and economic outputs - dwindle.
People are likely to be lonelier, with extended families - or even families - becoming a thing of the past. Demographer Nicholas Eberstadt, of the American Enterprise Institute, says: 'For many people "family" would be understood as a unit that does not include any biological contemporaries.'
He adds: 'Most of the biological relatives for many people - perhaps most people - will be their ancestors'.
Peter G. Peterson writes in his book Gray Dawn: 'Throughout history, most people who reached old age came to know personally far more of their descendants than their ancestors. In the near future, this will be reversed.
'It is likely you will never get to know as many of your children (and their children) as of your parents, your parents' parents and so on.'
The decline of rich nations is also likely to change the balance of global political power. In 1950, 32 per cent of the world's population lived in developed countries. By 2050, it will be just 12 per cent. Europe - which had a quarter of the world's population in 1900, but will have just 7 per cent by 2050 according to UN projections - will become a marginal force. It will be overtaken by Latin America, whose share of the world's population will double to 9 per cent; and dwarfed by Africa.
In 1900, Europe had three times the population of Africa; by 2050, Africa will have three times the population of Europe. In 1950, six of the 12 most populous countries were in the developed world; by 2050, the US will be the only developed country in the top 12.
But nature - and humanity - abhors a vacuum. Peterson writes: 'Perhaps the most predictable consequence will be massive immigration pressure on older and wealthier societies facing labour shortages.'
Sweden has managed to arrest the decline in its birth rate in part through the introduction of more favourable tax status for parents.
Stephen Radley, chief economist at the Henley Centre, the forecasting think-tank, says fiscal fertility schemes are unlikely to have much impact. 'I think that governments will be forced to relax their stance on immigration,' he says. 'And I think the UK is even more likely to do this than other European countries, given our history on immigration. We have, uniquely in Europe, absorbed Eastern and Asian culture in a big way.'
If we are short of people, it seems certain that - as in the past - we will simply throw open our national borders until the balance has been redressed.
Radley says the only other policy change that could help to reverse the decline is a rebalancing of work and family life.
'If parents are able to continue in their careers more easily, if the workplace culture changes, then that could impact on decision-making on children,' he says.
Parental leave, albeit for 13 weeks and unpaid, is a step in the right direction, he says - although the fact that the Daily Mail, the 'paper of the family', described even this modest measure as a 'another blow for business' shows just how far attitudes towards supporting parents in the workplace need to change.
Of course, a lot of things can change in 1,000 years. But what is frightening about the forecast is that it's a mathematical certainty if Japanese women carry on having just 1.4 children each on average - and if Japan doesn't change its immigration policy. If things continue as they are, the Japanese will die out. It's just a question of when.
And so will we.
Britain is one of 61 countries that are not having enough babies to replace their populations, according to the United Nations. For a population to remain stable, women need to have 2.1 babies each on average. In the UK, women are now having just 1.7 babies. One in four women are now opting to have none at all.
In all the countries of the European Union, fertility is now so low that populations are set to decline - if they haven't already. Spanish women - having just 1.15 babies each - have the lowest fertility in the world. In some parts of Spain the average rate has dropped below one.
The European Commission says fewer babies were born last year in the EU than in any year since the Second World War.
'Obviously, the social structure is going to change dramatically in the next century,' says John Clarke, professor of geography at the University of Durham.
'We are going to become used to a world with no-child and one-child families, and with a growing proportion of older people. Siblings will become rarer and rarer.'
Clarke points out that the unprecedented 'birth dearth' is even spreading to some developing countries. Women in India now have fewer babies than American women did in the 1950s, while in China, Cuba and Thailand women are already having too few babies to replace themselves.
After centuries of population growth, and decades of apocalyptic warnings about the population bomb, most of the developed world is now facing a 'population bust'. In his landmark 1968 book, Population Bomb, Professor Paul Ehrlich warned that 'we will breed ourselves into oblivion'. Thirty years later, demographers say he is right - but not in the way he expected.
Even a few years ago predictions abounded that the exponential growth in the world's population would mean that by around 3000 there would be standing room only on the planet. One demographer predicted the impossible, claiming that in the fifth millennium humanity would outweigh the planet itself.
But the unexpectedly sharp decline in fertility around the world has forced all forecasters - including the UN - to downgrade their predictions. There are now 6 billion people in the world, and while the UN's best guess is that the global population will reach 9bn by 2050, it admits the total could peak as low as 7.5bn by 2040 before falling back.
Almost all that growth will be in Africa and Asia, outweighing sharp falls in much of the developed world. The UN predicts that by 2050, Russia's population will have declined by 25 million people, Japan's by 21m, Italy's by 16m, and Germany's and Spain's by 9m each. Britain, with a younger population and more babies, is less affected - at least initially. The UN forecasts the British population will drop by 2m by 2050 before the decline accelerates.
The most catastrophic fall will be in Estonia, which is set to lose more than a third of its population in the next 50 years.
Samuel Preston of the University of Pennsylvania reckons Europe will lose 24 per cent of its population by 2060. The UN forecasts that Europe and Japan will lose half their population by 2100.
All this is not just crystal ball gazing. The European Commission says the 'natural' populations of Germany, Greece, Italy and Sweden fell last year - with only immigration ensuring that the overall populations remained steady. The populations of all but two of the countries in central and Eastern Europe fell in 1997, with Latvia's dropping by almost 1 per cent.
Of course, longer-term projections are shaky. 'We really do have to differentiate between shorter-term projections, say up to 30 years, and the longer-term ones which by definition are highly speculative,' Clarke says.
Nonetheless, he says, there is little prospect of a dramatic change in the fertility figures. 'The main factors driving the change are changes in social attitudes towards smaller families and the decline of the extended family, and even more important, the huge change in the status of women as they enter the labour market in greater numbers. I don't see, for the foreseeable future, much chance of an increase in family size.'
The implications of the birth dearth are potentially as far-reaching as those of the population bomb. Most debate has focused on the related issue of an ageing population, and the crippling cost of providing pensions, but a falling population presents problems of its own.
Housebuilders will become as outdated as cartwrights;
property prices will fall as ghost towns proliferate.
Traffic jams and overflowing trains will be things of the past.
The environment - or what is left of it - will benefit as
fewer people pollute less.
The military may have to raise maximum ages to fill the ranks;
schools will need to be remodelled as lifelong learning centres or knocked down.
Businesses brought up on expanding markets will have to get used to a shrinking customer base. Workforces will shrink, eradicating unemployment and creating labour shortages. In just 10 years, the population of working age will be contracting by 1 per cent a year in Italy, Germany and Japan.
Countries hooked on permanent economic growth will have to adapt to permanent recession, as their populations - and economic outputs - dwindle.
People are likely to be lonelier, with extended families - or even families - becoming a thing of the past. Demographer Nicholas Eberstadt, of the American Enterprise Institute, says: 'For many people "family" would be understood as a unit that does not include any biological contemporaries.'
He adds: 'Most of the biological relatives for many people - perhaps most people - will be their ancestors'.
Peter G. Peterson writes in his book Gray Dawn: 'Throughout history, most people who reached old age came to know personally far more of their descendants than their ancestors. In the near future, this will be reversed.
'It is likely you will never get to know as many of your children (and their children) as of your parents, your parents' parents and so on.'
The decline of rich nations is also likely to change the balance of global political power. In 1950, 32 per cent of the world's population lived in developed countries. By 2050, it will be just 12 per cent. Europe - which had a quarter of the world's population in 1900, but will have just 7 per cent by 2050 according to UN projections - will become a marginal force. It will be overtaken by Latin America, whose share of the world's population will double to 9 per cent; and dwarfed by Africa.
In 1900, Europe had three times the population of Africa; by 2050, Africa will have three times the population of Europe. In 1950, six of the 12 most populous countries were in the developed world; by 2050, the US will be the only developed country in the top 12.
But nature - and humanity - abhors a vacuum. Peterson writes: 'Perhaps the most predictable consequence will be massive immigration pressure on older and wealthier societies facing labour shortages.'
Sweden has managed to arrest the decline in its birth rate in part through the introduction of more favourable tax status for parents.
Stephen Radley, chief economist at the Henley Centre, the forecasting think-tank, says fiscal fertility schemes are unlikely to have much impact. 'I think that governments will be forced to relax their stance on immigration,' he says. 'And I think the UK is even more likely to do this than other European countries, given our history on immigration. We have, uniquely in Europe, absorbed Eastern and Asian culture in a big way.'
If we are short of people, it seems certain that - as in the past - we will simply throw open our national borders until the balance has been redressed.
Radley says the only other policy change that could help to reverse the decline is a rebalancing of work and family life.
'If parents are able to continue in their careers more easily, if the workplace culture changes, then that could impact on decision-making on children,' he says.
Parental leave, albeit for 13 weeks and unpaid, is a step in the right direction, he says - although the fact that the Daily Mail, the 'paper of the family', described even this modest measure as a 'another blow for business' shows just how far attitudes towards supporting parents in the workplace need to change.
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