Conflicting demands for natural resources such as coal, oil, and gas mean that we are quickly running out of these finite sources of energy. But it's not just fossil fuels that are a problem, as even our water resources are getting low. So how much do we really have left? And what alternatives can we use instead? Read on to find out.

Primarily used as fuel to generate electric energy, coal has the largest reserves of any natural resource left. According to the World Coal Association, there are approximately 1.06 trillion metric tons still remaining. This gives us about 132 years before it runs out, down from 150 years in 2018. 

Coal is burned so that its heat can convert water into steam, which then turns a turbine and leads to the production of electricity. There are several renewable options to coal, but the best is thought to be geothermal energy, which can create the same effect without depleting the earth's reserves. Geothermal energy involves extracting heat from the earth's core to turn the water into steam.

Although natural gas consumption fell by 2.3% in 2020, this finite fossil fuel is running dangerously low. If things go on this way, we may only have 52.8 years of gas left, according to research conducted by BP and published by Our World in Data.

Many believe that nuclear power is the best alternative to fossil fuels such as natural gas since it releases very little carbon and other pollutants into the air. It's also a very efficient energy source, only using a small amount of uranium to produce a lot of energy, and it's relatively cheap to run a nuclear power plant once it has been built. That said, nuclear power does have risks. Incidents such as the disaster at Chernobyl have turned many people against this energy source.

According to BP's Statistical Review of World Energy 2020, oil consumption fell to its lowest levels since 2011 as a result of the coronavirus pandemic. This meant supply was falling by a staggering 9.1 billion barrels per day. But although this fall in demand may have bought us a little more time – current estimates suggest we have 50.7 years of oil left, up from 50.2 in 2018 – we've still reached crisis point. We rely on oil not just to power our cars and vehicles, but also to make different plastics and synthetic materials. 

Despite this, the US is having a fracking boom. Hydraulic fracturing, known as fracking, uses water to extract oil and gas trapped in shale and other rock formations underground. According to the American Petroleum Institute (API), the fracking industry now supports 5.6% of US employment – but this comes at a serious price. By 2025, methane leakages during fracking could cost the US almost $30 billion a year in health damages, says the Natural Resources Defense Council (NRDC). 

Electricity is becoming the most popular alternative fuel for vehicles that run on gasoline or diesel. Electricity is most often produced by coal, which currently accounts for 37% of global production. By 2040, the International Energy Agency (IEA) expects this figure to fall to 22% as reliance on renewable energy sources such as solar and wind increase. But what about the plastic products that we need oil for?

Starch-based polymers or bioplastics have had a lot of attention as a potential solution to replacing plastic. Not only are products made from food waste, woodchips or vegetable fats completely biodegradable, but they're also much cheaper to produce than plastic. By 2025, European Bioplastics estimates the global bioplastics production capacity will increase to 2.87 million metric tons. This is a good start, but considering more than 368 million metric tons of plastic are produced a year, we've still got a long way to go. 

The fashion industry is one of the most polluting sectors in the world. The International Union for Conservation of Nature (IUCN) claims textiles are responsible for 35% of primary microplastics in our oceans, mainly from the production, washing, and wearing of polyester clothes. To prevent this, biodegradable fabrics such as lyocell are becoming a popular alternative. Made from wood pulp, lyocell won't shed microplastics during use and requires up to 50% less water than cotton.

When we think about natural resources, most of us don't think about phosphorous, but without this crucial mineral we'd struggle to survive. Phosphorous is necessary for a range of biological processes, from growing plants to developing new bone cells. Unfortunately, our reliance on phosphate fertilizers in modern farming has led to overextraction of the element. Research by the Global Phosphorous Research Initiative predicts we'll run out of phosphorous in the next 30-40 years, posing a serious threat to our food production rates. 

But all is not entirely lost. Phosphorus levels in bone can reach between 10% and 13%. Although bone meal – steamed and ground animal bones – is not a complete fertilizer, and is not as powerful as current fertilizers, the slow-release bone meal fertilizer offers a more sustainable alternative if we start to make the switch now. The best bones for phosphorus? Beef.

"There will be no water by 2040 if we keep doing what we're doing today." This is the harrowing prediction from Professor Benjamin Sovacool of Aarhus University, Denmark, and other forecasts aren't much brighter. According to the International Resource Panel, half the world's population could be living in areas that don't have enough water to go around by 2030. Fresh water only makes up 2.5% of the world's water, with the rest being undrinkable salt water. To add to the problem, 70% of fresh water is actually in the form of ice and permanent snow. It's not just drinking that we need fresh water for, but for washing and to produce food. High demand means we could soon run out. So what can we do? 

Desalination plants like this one in Hamburg, Germany might be the answer. Processes such as reverse osmosis (which filters out the salt) or distillation (which boils the water and collects the water vapor) are in use in the Middle East and Israel, with the latter actually getting 40% of its water from desalination. These processes aren't without their downsides though. Both are very costly, harmful to marine ecosystems, and take up a lot of energy. According to Energy Central, one desalination plant uses as much power as a jumbo jet.

A greener alternative to desalination is wastewater treatment. By recycling wastewater and household sewage, we could drastically boost our reserves. The Shafdan Wastewater Treatment Facility in Israel, for example, supplies water to more than 50,000 acres of farmland a year. Over 40% of Israel's agricultural water needs are now met by wastewater, while methane in the remaining sewage waste is used to fuel renewable energy production. 

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