What are the sustainability challenges of our generation?

The biggest challenges of our generation

Overshoot Day

For most people July 29, 2019 was a day like any other. People woke up, had breakfast, brought their kids to school, went to work, had dinner with their family, watched some television or went to the gym. Nothing special, right? Except that Mondayjuly 29, 2019 was in fact an important milestone for everyone on the planet: it was Earth Overshoot Day 2019.1

Overshoot Day is the date each year on which the global population is estimated to have consumed all the resources that planet Earth is able to regenerate in a year. In other words, by this day on Mondayjuly 29, 2019, humanity had already extracted more out of the planet in terms of resources and materials than the earth could replenish in that year. And we had put more pollution into the system than the planet could remove.

This is a big deal.

Compare this planetary dilemma to a family having enough income at the beginning of each month to last at least the rest of the month.

Preferably, there is something left over at the end of the month to save some for a rainy day or for an investment. Instead, all the money is already spent by the third week. The family, in need of groceries, paying rent and expenditures, has to borrow money to make it through the rest of the month. The borrowed money needs to be paid back with interest the following month, reducing the money that is available next month. Sure enough, the next month again the same thing happens. Only this time, since they had to pay interest on the borrowed amount last month, they have less disposable income to start with, and as a result they run out of money even sooner. On top of that, the family decides to spend even more. Clearly the income for that month will not be sufficient, and the family needs to borrow even more to cover both the interest and the increased spending. The next month this happens again. More interest needs to be paid, and again they increase their spending. This goes on month after month. Slowly the amount of money they have at the start of the month will be increasingly less sufficient to make it through a month. Until one day...

When we talk about Earth Overshoot Day we, of course, don’t talk about borrowing money that we have to pay back with interest. But it is still a good analogy. In reality, we are talking about taking more resources out of forests, oceans, biodiversity, the soil and the atmosphere than the Earth can replenish. Each year we increase what we take out. And we are not paying it back. Each year we are further diminishing the Earth’s capacity to clean up pollution or restore damage to living resources. As a result, Overshoot Day is coming earlier and earlier every year. Until one day...

As shown in Figure 1.1, during a 20-year period from 1980 to 2000, Overshoot Day went from early November (a two months deficit) to 1 October (a three months deficit). During the next 18-year period, this process accelerated. Between 2000 and 2018, Overshoot Day went from 1 October to 1 August — a five month deficit. Overshoot Day is now two months sooner! This is alarming news.

The Global Footprint Network, which is the organization that calculates Earth Overshoot Day, estimates that to maintain our current level of consumption we would need 1.72 planets like the Earth’. Our rate of consumption is accelerating, and there are no signs that it is slowing down. If we continue like this over the next 50 to 60 years we will be on 100% overshoot at the beginning of each year. For most of us that will

Overshoot Day is coming earlier every year. Original model from Global Footprint network

Figure 1.1 Overshoot Day is coming earlier every year. Original model from Global Footprint network.

happen in our lifetime or the lives of our children, unless we change the direction we are going.

Staying within planetary boundaries

Overshoot Day is just one approach to measure our level of unsustian- ability as a society. There are others models that are useful to understand how serious the situation is.

In 2009, a group of environmental scientists, led by Professor Johan Rockstrom, published Planetary Boundaries: Exploring the Safe Operating Space for Humanity. This study outlines nine key ecological processes that are being severely affected by human activity and suggests that “pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded”4. Rockstrom et al. concluded that changing these natural processes by too big a margin or too quickly could be catastrophic for human life and wellbeing.3 Consequently, they proposed limits or boundaries for these processes; staying within those boundaries should allow a “safe space for human development” and avoid large-scale, planet-wide changes to the environment on which all of us depend totally for our existence.6

These key planetary processes are:

  • 1. Freshwater consumption;
  • 2. Climate change;
  • 3. Land use/conversion and degradation;
  • 4. Biodiversity loss;
  • 5. Ocean acidification;
  • 6. Depletion of the ozone layer;
  • 7. Chemical pollution;
  • 8. The release of aerosols into the atmosphere (air pollution);
  • 9. Disruption to the biogeochemical cycle (e.g. through excessive use of nitrogen-based fertilizers).

For seven of the nine processes, scientists have calculated quantifiable, measurable targets that are absolute limits to what our planet can sustain.' They put maximum number limits on how much we can pollute, destroy, take or eliminate and still get away with it. For two of the nine processes, they have been unable to agree on quantifiable boundaries for chemical pollution and atmospheric aerosols (a type of air pollution) for now. These boundaries are crucial, but for the time being, without a limit, we simply do not know if we are overshooting them or not.

Of the seven planetary boundaries with absolute quantifiable targets, we do know we are already exceeding four of them in absolute terms. These boundaries are:

  • • Changes to the global nitrogen cycle;
  • • Climate change;
  • • Land-use conversion;
  • • Biodiversity loss.

The term “exceeding” in the previous sentence is an understatement. The data are very disturbing. Let’s look at the current facts on these overshoots. Hold on to your hat.

Overshoot one: nitrogen, the unknown killer

Most of us are familiar with nitrogen as the letter N in chemistry. It is widely available on this planet and used for many valuable purposes like food preservation production, refrigeration and as fertilizer to increase yields of agricultural production. However, most of us do not know that nitrogen is also a major source of pollution. When it comes to the quantity of nitrogen being used, we’re currently operating at almost 150% above a sustainable level. The global boundary for nitrogen is 62 million metric tons per year, but the actual use in 2015 was 150 million metric tons8. Note that these are global averages. As you can imagine, the maximum targets used will vary substantially based on soil type, climate, and environmental system.

More than two-thirds of atmospheric emissions of nitrous oxide arise from processes in soils, largely resulting from application of nitrogen fertilizers.4 The use of nitrogen fertilizer has risen from 11 million tons in 1961 to 108 million tons in 2014.'" Besides these chemical fertilizers, other sources of excess nitrogen include animal manure, discharged wastewater, use of fossil fuels in cars and industry, but also some of the soaps and detergents we use at home.

Excess nitrogen in the environment can have many consequences for water, soil, human health, and other aspects. All these problems, however, do not occur at the same rate or with the same intensity. Instead, they follow a sequence of effects from one environmental system to the other; this is called the nitrogen cascade.

Some systems, such as rivers and lakes, are quickly affected by excess nitrogen, but other systems, such as soils, can accumulate nitrogen for a longer period. As a result, the effects of excess nitrogen are very divergent. These effects include the following11:

  • • Excess nitrogen in the form of fertilizers is leached away — almost 50% of it is not absorbed by plants — and enters our water systems, resulting in serious eutrophication of freshwater systems and acidification of terrestrial ecosystems. This leads to rapid algae growth, which impacts the ecosystems of water bodies by blocking sunlight, using up oxygen for other species and releasing toxins that are harmful to animals.12 As a result, excessive nutrients like nitrogen in the water can cause a “dead zone”: oxygen-deficient areas in which nothing can live. In March 2004, the UN Environment Program published its first Global Environment Outlook Yearbook in which it reported 146 dead zones in the world's oceans where marine life could not be supported due to depleted oxygen levels. Some of these zones were as small as a square kilometer (0.4 mi2), but the largest dead zone covered 70,000 square kilometers (27,000 mi2). A study in 2008, four years later, reported a total of 405 dead zones worldwide;13,14
  • • Nutrient pollution in the air also causes acid rain which in turn affects lakes, forests and animals.'3 Acid rain has very damaging effects on life on land and below water. A healthy lake, for example, has a pH of 6.5 or higher. Acid rain causes the pH to fall below 5, which is detrimental to fish life. At a pH below 4, the lake is biologically dead.16 Some lakes in Sweden have become so acidic that they are no longer able to support fish life.17 Acid rain also decreases the pH range for growth, which is between pH 5 and pH 8. Plants stop growing if the pH falls below 3.7.18 In Poland about 50% of the forests have been damaged by acid rain19; this figure is about 30% in Switzerland;
  • • Nitrous oxide is also a particularly potent greenhouse gas; it is over 300 times more effective at trapping heat in the atmosphere than carbon dioxide over a 100-year period;2"
  • • Airborne nitrogen compounds such as nitrogen oxides (NOx) also contribute to the formation of air pollutants such as ground-level ozone (a component of smog), which in turn is detrimental to vegetation and animal life;21
  • • Nitrogen emissions such as ammonia and NOx contribute to particulate matter, which cause respiratory problems and cancers, as well as damage to plants and forests;22
  • • Biodiversity loss is another consequence. As a result of the nitrogen build up, most living creatures in terrestrial, freshwater and coastal water systems suffer due to eutrophication and acidification of water and soils.23

In Europe alone, the environmental and human health costs of nitrogen pollution are estimated to be between €70 billion and €320 billion per year.24 This makes nitrogen one of the most unknown, least understood and costliest of all pollutants.

The fact that excess nitrogen is increasingly seen as one of the most important causes of environmental damage was happening at the time of publication in our own country. The issue of nitrogen was prominently in the news. The highest judicial authority in the Netherlands ruled that the current Dutch policy to mitigate the negative consequences of nitrogen in agriculture, industry and traffic is insufficient and thus invalid.23 The consequences of this verdict are serious and may incapacitate several economic sectors. Concretely, it means that hundreds of licenses for farms, industries, infrastructural projects and housing projects are likely to be suspended, as they are likely to harm their direct surroundings. This will cost hundreds of thousands of jobs and will put the economy into a recession. To stay within the nitrogen emission limit, plans are being made to reduce the numbers of livestock on virtually all farms in the Netherlands by 50% and to lower the maximum speed limit on motorways. A highly unpopular measure that reflects just how serious this issue is being taken by politicians.

Overshoot two: climate change is already here

The second alarming overshoot concerns climate change. According to scientists, the situation has reached critical levels. Currently there are 408 ppm of C02 in the Earth’s atmosphere, well above the 350-ppm considered to be a safe level.26 As a result, according to the IPCC we are heading towards serious, long-term climate disruption, melting polar ice sheets and even more pressure on water supplies due to the loss of glacial freshwater supplies.27,28

The sad news is that we have already accepted that climate change is inevitable. The ongoing climate talks that have been held since the Paris Agreements are about whether we can accept 1.5 or 2 degrees of warming. The difference between the two options is enormous. Here are a few examples of the consequences of a 2-degree increase compared to a 1.5-degree increase.

  • • A thawing permafrost. A 2-degree rise in average global temperatures means that 6.6 million km2 of arctic permafrost will thaw; at 1.5 degrees this will be “only” be 4.8 million km2, a difference of
  • 38%;
  • • Ice-free summers in the arctic. A 2-degree rise means that ice-free summers in the arctic will occur at least once per decade, but only once per century with 1.5-degree rise. This is ten times worse;
  • • Loss of coral reefs. A 2-degree rise will lead to the loss of almost 100% of coral reefs, while loss will be limited to a 70% to 90% decline at a 1.5-degree rise;24
  • • Severe heat waves. At a 2-degree rise, 37% of the global population will be exposed to severe heat waves at least once every five years, but only 14% at a 1.5-degree rise. This is 2.6 times worse.;
  • • Loss of plant habitats. At a 2-degree rise, 16% of plant species will lose at least half of their range, but only 8% at a 1.5-degree rise.;
  • • Lower crop yields. At a 2-degree rise, maize yield in the tropics will decline by 7%, but only by 3% at a 1.5-degrees rise. This is 2.3 times worse.

But this is all theory for now. According to the International Panel for Climate Change (IPCC), the reality is that cumulative current measures announced by the governments supporting the Paris Agreements will not be enough to keep the temperature rise below 1.5 degrees or even 2 degrees. Instead we are heading for an increase of 3 degrees. As you can imagine, this will irreversibly change life on earth.30

Although we are just at the start of this rapid increase in global temperature, the effects are already apparent. Since 1972, the global average temperature has been above average every single year for 42 years.31,32 The five years before this book went to press were the hottest in recorded history33,34 and as a result we witnessed the most destructive hurricanes35 and wildfires36 in recorded history. In 2017, 2018 and 2019 we saw unusually hot summers across the Arctic region, Europe, Latin America, parts of the United States and Australia resulting in disastrous droughts and almost uncontrollable wildfires in Spain, France, Greece, Portugal and even in northern regions such as the UK, Denmark, Sweden, Finland and northern Russia.

In other parts of the world, there are equally grim realities and future prospects that are directly linked to climate change. In 2018, Cape Town in South Africa experienced its worst drought in over a century37

Australia had a one-in-a-thousand-year drought from 1995 to 2009.Then, in 2010, this reversed completely when, Australia experienced its worst flooding in half a century when an area of Queensland (larger than France and Germany combined) flooded, affecting 200,000 people and costing at least S10 billion. And at the end of 2019 Australia was yet again experiencing record temperatures and hundreds of uncontrollable blazing forest fires.

Drought in Spain’s northeastern region of Catalonia grew so severe in 2008 that Barcelona began importing water by ship from France.

Southeastern Brazil, including the cities of Sao Paolo, Rio de Janeiro and Belo Horizonte, is struggling through the worst drought in 84 years, with 40 million people and the nation’s “economic heartland” at risk. As a result of unusual droughts and bad conservation policies, Brazil is experiencing the worst forest fires ever seen in the Amazon. According to the BBC, the official figures show that more than 87,000 forest fires were recorded in Brazil in the first eight months of 2019. In June 2019 alone, more than 2200 km2 was burned, an absolute record.38

California, in the USA, is also facing unprecedented drought, now in its fourth year, resulting in devastating and uncontrollable wildfires. The 2018 wildfire season in California was the deadliest and most destructive on record, with a total of more than 8,500 fires burning an area of 1.89 million acres (766,439 ha), the largest burned area recorded in a single fire season, according to the California Department of Forestry and Fire Protection.39 When we talk about falling water tables due to drought, the most severe declines can be seen in northern India, where the effects of the droughts can even be observed from space.4"

Overshoot three: land conversion and land degradation

The most recent overshoot in absolute terms concerns land use and land conversion. Land conversion refers to the permanent transformation of natural habits such as forests, grasslands and wetlands into agricultural land.41 The most important and most devastating conversion is that of forests to “non-forested” systems, such as agricultural land.42 Land degradation is generally understood to be the reduction or loss of biological or economic productivity.43

The World Wildlife Fund (WWF) estimates that approximately 18.7 million acres of forests are lost worldwide per year, which is equivalent to the area of 27 soccer fields every minute. Industrial agriculture (i.e. the industrialized production of livestock, poultry, fish and crops), along with subsistence agriculture, is the most significant driver of deforestation in tropical and subtropical countries, accounting for 80% of deforestation from 2000 to 2010. Industrial agriculture is responsible for 30% of deforestation in Africa and Asia, and for 70% in Latin America.44 According to the WWF, 15% of all greenhouse gas emissions are from deforestation.

In total, 24% of all land worldwide is degrading or has already degraded.45 That is one-quarter of all the available land on this planet. One of the worst types of land degradation is desertification, defined as the process by which fertile land ultimately becomes a desert, typically as a result of droughts, deforestation, erosion, inappropriate agricultural practices, monoculture and irrigation, overgrazing and chemical pollution.46,4' Currently over 12 million hectares of arable land, an area almost the size of the United Kingdom is lost to drought and desertification every year.48 As a result of desertification and land degradation S42 billion of income for local economies is lost every year.46 The UN has calculated that the livelihoods of more than one billion people in some 100 countries are already threatened by desertification50, and by 2045 some 135 million people may be displaced as a result.31 Conversely, restoring the soils of degraded ecosystems has the potential to sequester up to three billion tons of carbon annually52 and will enhance local economies, improve livelihoods, slow biodiversity loss and stop the migration of tens of millions of people to Europe and the USA. Reversing land degradation and deforestation appears to be one of the most effective strategies to tackle multiple problems at the same time.

Overshoot four: biodiversity loss - the most important indicator of all

The fourth alarming overshoot concerns biodiversity loss and is probably the most important indicator of all. Biodiversity is defined as the total spectrum of animal, plant and insect species living on earth. Together they make up the web of life and the cradle of life. Biodiversity loss is largely the result of the effects of the other overshoots discussed above.

Unfortunately, the overshoot on this target is the most extreme of all. Populations of vertebrate species (such as mammals, birds, reptiles and most fish) have declined by 60% in less than 50 years.53 Populations of invertebrate species (such as insects) have also experienced staggering declines averaging 45% over the past 40 years.34 This amounts to between 150 and 200 species of mammals, birds, insects and plants that become extinct every day. 3 In Germany, a 30-year study reported a 75% decline in insect biomass over this period, indicating rapid loss of habitat and healthy environments for these species.56 This loss of species is around

1,000 times higher than what scientists consider a natural rate of extinction and is the highest level the world has seen since the dinosaurs were unceremoniously wiped off the face of Earth 65 million years ago.37 A recent report from the United Nations (2019) has predicted that we will lose another one million species of the eight million remaining species before 2030. This loss of species is so high that scientists are calling it the sixth major extinction event in the history of the Earth, and the first to be driven by human activity.58 To bring biodiversity loss below a safe planetary boundary would require that rate to decrease 10-fold to 100-fold.59 Aside from the ethical consideration of eradicating over 60,000 species every year, this loss of animal and plant life is completely unsustainable if we want to stay healthy and robust, and ensure the survival of the human species as well.

The major drivers for loss of biodiversity and species decline are ranked as follows in declining order: deforestation, unsustainable agricultural practices like monoculture, chemical use, over use of fertilizer, overfishing, hunting for bush meat and poaching, climate change, pollution, and invasive alien species. All of these are the result of human activities.

Please let that last sentence sink in.

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