Commercially-available solar panels are composed of solar cells that are most often made from various forms of silicon. Some panels use thin-film cells made from other semiconductor materials. Solar cells utilize a property of semiconductors that allows them to convert light energy into electrical energy.
Less than 10% of discarded plastic is recycled. This is one of the major reasons that plastic waste is such a threat to the environment. There are many challenges to recycling plastics. For one thing, there are many different types of plastic and if they are melted together, they tend to phase-separate like oil and water and the resultant substance is structurally weak. Sorting plastics by type is not a simple task. More generally, it is very difficult to produce plastic with its original properties from recycled feedstock. So recycled plastics generally end up being useful in only more limited applications.
Protecting biodiversity is a critical challenge facing humanity. Global vertebrate populations – from elephants to amphibians – declined by 58% from 1970 to 2012 and losses are expected to reach 67% in the next two years. Think about it: at least two-thirds of all vertebrate animals on earth have vanished over the lifetime of anyone fifty years old or over.
Global bee populations have been drastically declining as a result of habitat loss, pesticides and climate change. But studies are showing that planting flower patches in urban gardens and green spaces can make a real difference in restoring natural pollinators. There are already positive results in cities from Chicago to London to Melbourne.
Grizzly bears once roamed much of North America and symbolized the continent’s untamed wilderness. But hunters and trappers nearly wiped them out across most of the Lower 48 states by the late 1800s.
One of the most exciting possibilities for future solar energy technology is that of solar cells that can be sprayed or printed on to surfaces like the windows of skyscrapers, the roofs of sports utility vehicles, or the walls of houses. And the expectation is that such technology would be far cheaper than today’s silicon-based solar panels.
The circular economy refers to the concept of an economic system in which there is no waste. Materials are recycled, repurposed and reinvented to create new raw materials thereby reducing the need to extract new resources and thus saving money, energy and water resources.
The average global temperature is one degree Celsius above pre-industrial levels. There has long been a goal to limit global warming to no more than 2 degrees above those levels. But the Paris climate conference has set a more ambitious goal of limiting global warming to 1.5 degrees. What difference would that half a degree make?
Water is a simple chemical compound containing two hydrogen atoms and one oxygen atom connected by covalent bonds. It covers 71% of Earth’s surface and is vital for all forms of life. Despite its abundance, water that is safe for drinking is globally in short supply.
