Unfortunately, all these ships cause a lot of pollution. Many port cities worldwide are suffering from poor air quality. Ships are a much more efficient way to transport goods than trucks, trains or planes. Yet the sheer size of the industry - shipping carries about 90 per cent of global trade - means ships still contribute about 3.5 per cent of global carbon dioxide emissions.
Hong Kong waters are teeming with tugboats, which are used to help larger ships manoeuvre to the docks. Tugboat engines are powerful relative to the size of the vessel and they use huge amounts of fuel. This affects the environment of port cities from Los Angeles to Shanghai. The exhaust from diesel engines can cause cancer and respiratory illnesses.
Los Angeles and Long Beach, the largest container ports in the US, have introduced the world's first hybrid electric tugboat. The boat, named Carolyn Dorothy, costs US$1.35 million. It has four diesel engines and 126 batteries to store energy. Scientists have found that the green tugboat decreases emissions of soot by 73 per cent, nitrogen oxides (which cause smog) by 51 per cent, and carbon dioxide by 27 per cent.
One tugboat out of the thousands that work in all the ports around the world will make little difference, but it's a start. The new hybrid tugs are expensive, but the engineers who built the Carolyn Dorothy are already looking at ways to make the next tug even more efficient.
We think nothing of buying products imported from around the world. Many of those products were made with raw materials from other places even farther away.
As we demand more variety and cheaper prices in our everyday shopping, more and more ships are needed to carry raw materials and finished goods from one part of the world to another. Finding a cleaner way to move things around is an important part of taking better care of the earth.
Cameron is available to speak to students about environmental and climate change issues. Contact info@openpassage expedition.com