The environmental crises are all about how humankind exploits the planet.
I’ve put this here just for completeness; it’s described in its own section here.
Pollution happens when waste is left in the environment. Pollution can be deliberate but legal (e.g. fine particle air pollution from cars), deliberate and illegal (e.g. an oil-tanker cleaning its tanks out at sea) or a genuine accident (e.g. lead pollution from a fire in a church). Pollution passes the cost of dealing with the problem from the producer to someone else – it’s usually a deliberate business strategy.
The worst pollution problem today is that of greenhouse gases. Like many pollution problems it is long term – we are suffering from the pollution put out by previous generations. Given that the dead outnumber the living by a factor of 13, we’re lucky that our ancestors weren’t as ‘advanced’ as we are – in practical terms pollution has only been a serious problem for the last 100 years. But since then pollution has been a growing problem for following generations.
The climate crisis is affecting water quantity; but pollution is producing a less visible crisis with water quality that affects food production, health and can ‘cost’ an affected country or region 30% of its economic output. Fine-particle air pollution was the fifth leading cause of death worldwide in 2015. Plastic pollution seems to be everywhere, in the form of bottles, bags or microparticles; in the ocean, on the ice-cap, inside plankton (and thus being eaten by many marine animals), in our drinking water and in the stomachs of dead marine mammals. Much of mankind’s waste – pesticides, detergents, pharmaceuticals, cigarette stubs and even caffeine – end up in the oceans.
In many cases, we don’t know what this pollution will do to us or the planet; we often find a useful new technology (e.g. PCBs, asbestos, diesel) and then find out about the long term health effects later.
Benjamin Franklin said “When the well is dry, we know the worth of water.” Imagine how the citizens of Capetown felt when they were given a day zero when their water would stop flowing. Imagine living in Chennai (a modern city in India) and having your water supply cut (like 90% of the city’s population) and you have to get water from a public tap controlled by gangs. Imagine if you know the only drinking water available to you is polluted. Imagine spending most of your day worrying about water.
This is a reality for much of the planet. According to Wikipedia, two-thirds of the global population experience severe water scarcity at least 1 month of the year; half a billion people in the world face severe water scarcity all year round and half of the world’s largest cities experience water scarcity. The causes range from climate change, pollution, overconsumption by agriculture or industry, population growth and underinvestment in infrastructure.
Nature is full of complex food chains and systems where – through the miracle of evolution – species interact as though the had been ‘designed’ together. If a species is lost in some of these systems – for example bees pollinating flowers – then the entire system can break down; in this case, we get no fruit and nuts (or honey). Losing something at the base of a food chain – e.g. a type of plankton – can wipe out several species in a system in an area. Sometimes we can clearly see these effects – e.g. commercial fishing is less productive – and sometimes the result is more subtle – e.g. one species is wiped out, a second species replaces it in the system, but it has no natural competitors and it decimates a third species several years later.
But the very diversity of nature is failing; species numbers are declining and some are threatened with extinction. Crucially, 75% of flying insects in Germany have been lost in 25 years. Insects act as pollinators but also eat pests, decompose waste and are the base of many food chains. Most scientists think that ‘if the insects go, then so will we’. There are many other examples of threatened life-forms; corals that protect coasts, mangroves that purify water and birds that eat pests on crops.
There are many likely causes for this loss; climate change, pollution, loss of forests, overuse of pesticides and overfishing. Perhaps the most likely reason is the industrialization of agriculture; we cut down forests to farm more intensively and we rely on only a handful of industrially produced crops using lots of pesticides and fertilizers. As a personal, non-scientific observation, maize is cultivated near where I live; you can walk through these huge fields all day without seeing any animals – farmers included – or other plants; an industrial monoculture that seems designed to snuff out biodiversity.
Biodiversity is hard to understand and to explain, but many scientists feel its loss is more serious than climate change.
Modern intensive agriculture has allowed the planet to continue feeding itself as the population has grown. But – in addition to climate change and biodiversity problems already discussed – there are a few signs we may be reaching the limits of food production.
The first problem is that we are running out of agricultural land; if we want to grow more stuff, then we need to cut down forest and that increases climate change. This problem is amplified when we consider the growing demand for meat worldwide – it is a much less efficient way of using land to produce food.
The second problem is that agriculture is increasingly industrialized, with a handful of big businesses maximizing their profit at the expense of the community at large. Producing unhealthy but profitable food, polluting water streams, reducing employment, depleting soils and reducing biodiversity – these are all things that big agribusiness does. Compared to traditional farming, industrialized agriculture generates more greenhouse gas emissions directly (e.g. through the more intensive use of fertilizers) and indirectly (e.g. through more transportation, refrigeration and packaging).
Industrial farming seeks to maximize profit; a high level of mechanisation allows a few people to produce a lot of food. That’s one measure of efficiency; another measure is to sustainably feed a lot of people from a given amount of land. This second approach is more labor intensive – maybe using smaller fields and crop rotation rather than more fertilizer – but it’s better for the planet as a whole. Agricultural subsidies often disproportionately benefit industrialized agriculture – e.g. the EU’s CAP works by farm area rather than sustainability and the same sort of thing is happening in the UK.
Inside Climate News has an excellent article on the problems of industrialized architecture.