Are we on a sustainable path?
It was a question at the end of a course about sustainability held by the University of Illinois that I took a couple of months ago through Coursera.
It was a tough question since sustainability consists of many things that are interconnected to each other, and how can we measuring sustainability actually?
I toke some notes from the lecture and tried to sum it up.
So, first of all we need to know about the meaning of sustainable itself. According the UN definition “Sustainable is that we can meets the needs of the present without compromising the ability of future generations to meet their own needs”
Note that the descriptions is meeting the needs of people of today and in the future with the sources that we have.
The keyword “The needs” describes many items such as people who consume it, which is population, and what they consume: food, water, and energy. Energy is going to be a significant concern for the twenty-first and twenty-second centuries. Water also very important not just because we drink it or we use in our industrial processes, but it turns out that water is a limiting factor on increasing yields in agriculture (food). We can see that they all come together. And then if we solve all of them except for one, we might as well not have solved any.
So, let’s try to figure out these by one:
Population
It’s often said the root cause of all our environmental issues is overpopulation
There’s different types of population growth curves. One would be J shaped growth curve and other shape would be S shape. S shape growth curves are for systems that match the resources available. So they might grow quickly in the beginning but growth slows down as the carrying capacity, the maximal capacity that resources can support. While J shape its growth will slow at the beginning, and the growth increase exponentially till past the carrying capacity and system is not balance then it eventually crashes. S shape growth might be considered sustainable, whereas J shape growth is clearly unsustainable.
So we might consider asking ourselves question, is human society more like s shape or J shape? The two curves can look very similar for a very long time. And is our use of energy resource, a food resource, land, were near of its carrying capacity?
Global population is seven billion now. Most recent growth rates for world population is about 1%, and if that were to continue, so the global population will double in about 70 years. Imagine 14 billion people by 2080. What would happen if this came to pass?
But, first we need to know that the reason why there are many more people is because less people are dying. So the reason we are seeing of this population growth rate around the world today is not because there is going to be a jump in number of people being born relative to today, its because the people who are being born are going to live and are going to live for longer. So in some ways, the world increase in population is very hopeful theme because it indicates that people lives are getting better, more secure and healthier. In 1900, life expectancy at birth was 47 years in the United States, and between 45 and 50 years in Europe, Japan, and Australia. This changed quickly over the course of the century, US life expectancy at birth shot up to 68 years, by 1950, and is now 77 years in 2000. This increase has been due to many factors, increased sanitation, better standards of living, better medical care. This increase in life expectancy, or, its mean the decrease in death rates, has produced population booms. But these increases have stopped in many countries around the world today. Indeed, some countries, such as Japan and Germany.
We have these four stages of transition: in the first stage, we have high death rates and high birth rates, and they are matched, so that the population remains stable; in the second stage, the death rate plunges as new technology, improvements in standards of living, increased nutrition, medicine, sanitation, and so on, mean that more children reach adulthood and adults live longer this leads to a big boom in the population because the family sizes stay the same just as many children are born as before; and then there is the stage when the birth rate decreases and it comes down to match the new, low death rate; and finally, in the final stage, stage four, we see a balance between these two, so we have a new higher population because we’ve gone through this population boom but the population is no longer increasing. It appears that many developing countries are following this trajectory. So, let’s look at an historical example. This is the birth and death rates for the U.K., the United Kingdom:
Ecosystem and climate change
Population growth may not be the horror it could be, population growth rates are decreasing and they are on track to stabilize this century. It might infact be that for environmental sustainability consumption patterns have a much more bigger impact than population change will.
One of the sustainability threats that the earth faces is to its ecosystem and to extinctions of individual species. Before we look at human caused extinctions, we should be aware that there’s previous mass extinction were caused by enormous natural catastrophes. Geologists report that there have been five previous mass extinctions and that these caused by super volcanoes, giant asteroid strikes, massive worldwide climate change. As long as humans were exist, humans have been creating ecosystem change and extinctions. The International Union for Conservation of Nature says, that the current extinction rate is between 1000 and 10.000 times higher than the natural rate because we’re seeing significant habitat loss. In many places around the world, it’s been severely ecosystems reduced due to human action, such as over-exploitation of natural resources, logging of forest which can lead ecosystem degradation.
A lot of the systems are facing problems. They’re being degraded and polluted. They’re being used in ways that aren’t sustainable. Its can explained by simple idea called “Tragedy of the commons”. The tragedy refers to its inevitable destruction and commons refers to shared source that free no one own it and it used by many people.
Well, one example is we hold the atmosphere in common, no one person or one country owns the atmosphere. Every individual on earth breathes the same atmosphere. And so we all face the same incentives. We want to use the atmosphere for ourselves, but if we damage the atmosphere, that is shared amongst everybody else. Such as greenhouse warming, every individual use cheap fossil fuels, its creates pollution and damages the atmosphere as a whole. Similarly, the oceans and global fisheries that each fisherman from each country collect as many of resource for themselves as they can.
But actually, tragedy of the commons is not always inevitable. If we think of some of the classic places that have commons, like the Swiss Alps where Swiss farmers share common pasture lands. They’ve been sustainably used for hundreds of years. So, what reasons prevent a tragedy from occurring? There are three broad ways, the first way is personal action that is what individuals can do. The second way is internal governance or social pressures that is groups of people to do act. And the third way is some kind of external force, that is government intervention.
Energy
The modern world runs on energy and most of the energy we get today comes from fossil fuels. Coal and natural gas are very important in electricity supply because they have a very high energy return on energy invested. Energy returned on energy invested is the ratio of how much energy we get back on a given effort. The EROI of Coal is about 100. They also have many of the other advantages, they’re energy dense, they’re cheap ways to produce electricity, and they’re sources of supply that can be stored. But, it also produces other environmental affects, acid rain, mercury, and heavy metal contamination, ash, and sludge. And this has two big issues. The first one is the use of fossil fuels has impact on CO2 emissions that leads to climate change. Second problem is that fossil fuels are a finite resource. So, if we are talking in the sustainability context, we might wonder, do we have enough fossil fuels and what happens if we run out?
By moving to renewable energy sources, we can find new sources of power that are both sustainable, nonpolluting, and perhaps have other useful attributes. There’s lots of different types of renewable energy. The largest source of renewable energy currently is hydropower, is about ten percent of the U.S.’s electricity supply comes from hydroelectricity today. It’s have EROI little under coal and it can supply base demand of electricity. There are environmental impacts of using hydroelectricity however. They change the ecosystems of rivers and in particular they can impact the life cycles of fish.
Another suggestion of course, is solar photovoltaic cells or solar PV. Right now, this is a tiny source of energy around the world. But it’s a very quickly growing source of power. Solar power is growing exponentially. Similarly, wind power is also growing very quickly. It’s been doubling every three years or so, for the last decade. One of the drivers for all this growth is better technology, especially for solar cells. As solar cell technology improves, they become much more efficient. So, they capture more of the sun’s rays to turn into electricity. At the same time, the price of a solar cell has been decreasing year on year for decades. If this trend continues, we could see solar cells become cost-competitive with fossil fuels within around a decade. Renewables do have problems though. They rely on natural processes, the wind blowing, the sun shining, and so they can’t be relied upon as the base load for current energy grids. Another issue with electricity generated by these new renewable sources is that they’re not very good for transport. Currently, battery technology does not store energy nearly as compactly as fossil fuels do, batteries have very low energy densities. Similarly, biofuels are very highly land intensive. And they displace land that could be used for crops for growing food. Food versus fuel is a big issue for biofuels. Another worrying thing about the use of biofuels is that studies suggest that they also produce a lot of carbon dioxide. So then, although they might be in some ways a renewable energy source, they are not nonpolluting. Research continues into so-called second generation biofuels that might be more efficient. For example, Miscanthus grasses. But they still await technological breakthroughs before they can become useful. Is it even possible to move to a renewable energy future? It probably is, we would have to accept some changes.
This switch might be too painful for most nations. It would take decades to transition a grid and the technology breakthrough in tune with regulation support. And there is better way that some expert think, we could simply use less energy. Energy conservation is another way to consume energy sustainably. LED for example is consume much less energy than traditional electric lighting uses incandescent bulbs. There’s a lots of ways in the modern world that this could be achieved.
Water, Agriculture and Food
The Earth is a world of water, but most of this water is not usable, of course, for humans unless it’s expensively treated because it’s salty. Saline water in oceans, seas and saline groundwater make up about 97% of all the water on Earth. Only 2.5–2.75% is fresh water, including 1.75–2% frozen in glaciers, ice and snow, 0.5–0.75% as fresh groundwater and soil moisture, and less than 0.01% of it as surface water in lakes, swamps and rivers.
Modern society requires copious amounts of fresh water for domestic, industrial, and especially, agricultural use. Although water has the potential to be a renewable resource, because it’s powered by the sun which evaporates waters from earth surface, then gravity cycles that evaporated water back to the earth. But it can also be used unsustainably if the extraction rate of water from its sources is much higher than that natural recharge flow. In some places, water withdrawals exploit replacement rates, lowering water tables and depleting aquifers. In other places, water pollution is making stocks unusable.
If we were just using fluxes or the water flows, then we really wouldn’t have major sustainability issues anywhere, because all the water we would be taking out would be replaced each year. That’s a renewable use. But many places in the world are lowering water tables, we pump out lots of water from an aquifer, it actually lowers the groundwater level. As we subtract water from an aquifer, that is we take out water faster than it gets recharged through those natural hydrologic processes, the water table can drop. And of course as it drops we would need to dig deeper wells to extract the water and eventually of course we could use all the water up because we removed the stock entirely. This stock took a long time to emplace and in fact in some places the water under the ground is thousands of years old. So it could take millennia to replace if we extract this water faster than the natural flow would replace it.
This is a combination of a number of factors, but the leading cause of course is that we have an increased population and to feed an increased population, since agriculture is an enormous user of water. Water is very important in efficient agriculture. So there’ll be more pressure to extract more water to make more crops to feed more people. In some countries, the water use in industry is very important, and in others, domestic use is very important. But on average, worldwide, agriculture is the number one user of water.
Most water is used for agriculture. It is difficult to be precise, but here are some estimates people have used for various embedded water measures for different industrial and agricultural objects. It’s sort of like a hidden amount of water that was needed in their process. A kilogram of wheat requires about 1300 liters of water, while rice requires about 3500 liters of water per kilogram. Meat tends to require even more because most animals are fed crops that have been grown specifically as feed. So a kilogram of hamburger requires about 15000 liters of water.
We know that there is going to be another two to three billion people on the planet over the next 40 years, So we also know that we need to produce a lot more food. How are we going to do that? There isn’t that much virgin land available and also water. Estimates around 10% of earths land masses could be converted from virgin land into farm land. Potentially a little bit more than that if food prices climb. But, nevertheless, that’s not a satisfactory solution. Firstly, it might not be enough. And secondly, of course, this would mean that there’d be damage to the ecosystem in the natural world which we’d like to avoid. What’s more? There are other limitations to agricultural expansion. Lots of water is required to grow lots of food.
Modern farming uses many new technologies from 1565, of course, including things like tractors and equipment like that, but also there’s been enormous advances in plant breeding, fertilizers. And we now produce far more food for the same amount of land as we did in times past. In the past century, Increases in yields have been a much more important factor than increasing land under cultivation, for increasing total crop production. As a consequence, total world grain production has been going up for decades. It’s increased from around 1.25 tons per hectare to about 3.25 in the last 50 years. So, that’s almost three times as much, It’s an incredible increase. If this sort of trend is sustainable, we can feed a larger number of people without damaging ecosystems and, turning virgin land into farmland. Its called Green Revolution which is caused the increase of yield. It was very technology driven, drought resistance hybrids with more disease resistant genes, improving irrigation, and there were other big improvements as well. Some of which have not all been good of course, things like nitrogen ready crops that respond more to fertilizer. So, as a consequence, the amount of fertilizer applied over the last 50 years has increased enormously. If we worry about sustainability in agriculture, we have to think about fertilizer. And, the problem with fertilizer is that a lot of fertilizer is derived from fossil fuel inputs. There have been potential technical fixes to this in the future, but in the past, this has not been necessarily a sustainable growth pattern.
Another limit was water, and it’s being predicted that farmers will need to use 45% more water in 2030 than they do now, so that’s in less than two decades, if yields continue to grow at the current rates. They’re unlikely to get that much water. So, there might be technical fixes, but these will cost money. Things like improved irrigation, drip irrigation, or infrastructure invest in in developing countries particularly that there’s a lot of water loss through evaporation. Those would be expensive, we can provide more water and increase yields. But would point to food prices going up.
So, agricultural production in the twenty-first century looks like a challenging proposition. If we use the same techniques that made the original green revolution work, we might not be able to produce enough food to feed the coming billions. Or even if we are able to do that, costs will go up. And this will particularly impact people in poorer and developing countries where lots of this population growth is supposed to happen.
There is one relatively new technique that has been growing quickly over the last couple of decades that’s very controversial, but nevertheless, it might be a way out of this conundrum. That’s Genetically modified organisms might be able to produce their own fertilizer.
Toward sustainable path
There is a lot of destruction that has been done. We need to catch up and drastically reduce the destruction moving forward before we can confidently say we are on a path to a sustainable future.
UN SDG’s is a huge step in the right direction. The 17 goals aim to tackle all aspects of sustainability worldwide. Government policies, social responsibility, wealth, and technology, both locally in each country and globally, are key players to follow the path of sustainability. It’s quite possible that we may be on the way to sustainability, but we need to pick up speed.
[1] https://extraclass.com/e/neet-environment-3_Biotic__Potential_and_Enviromental_Resistance
[2] www.OurWorldInData.org/world-population-growth
[3] https://www.coursera.org/learn/sustainability/lecture/o0DZ1/demographic-transition
[4] https://www.macleans.ca/society/science/infographic-charting-the-worlds-sixth-mass-exinction/
[5] https://www.ren21.net/status-of-renewables/global-status-report/%5d
