Global Climate Change, previously referred to almost exclusively as Global Warming, is the rapid or significant change in climate around the world, and is usually referred to in conjunction with or dependent on man's activity on Planet Earth. While man's impact on the environment is easily seen in polluted rivers and overdeveloped forest areas, the farther impact on the Global Climate is harder to quantify. The current scientific consensus is that man's contribution of Greenhouse Gasses, coupled with general pollution from industry, is causing varied changes to climate around the world, probably to a negative benefit.
One of the most decried sectors of industry for pollution is the Transport of humans and cargo. During the 20th century, the petroleum engine's invention led the way in all transport, from ocean liners to cars to trains. All forms of public transport also used gasoline or diesel as their fuel until research started to indicate that emissions from these fuels were damaging the ecosystem and perhaps the atmosphere. One of the major studies showed a rise in Carbon Dioxide emission that corresponded directly with a rise in global mean temperatures. The push to regulate and eliminate greenhouse emissions has led to alternative fuel sources for public transport.
Improvements to public transport include the adoption of lighter vehicles, which puts less strain on the engine and so uses less fuel; lower horsepower engines; shared taxi or limo service, so more people are carried per trip; electric engines, so cars and buses don't idle and emit gasses; and new train engines, so commuters have a choice of transport while carrying cargo at the same time. Trains are actually the most efficient land transport system, as a single engine can carry over a ton of freight for 500 miles on one gallon of diesel fuel. However, trains are limited by their tracks and stations, and are not useful for short commutes or in-town travel. Subway systems are better for cities, but they must be put in place at enormous cost. Meanwhile, more efficient cars and buses, including hybrid vehicles, allow many more people to travel with decreased gas emissions.
According to the research, any reduction in Greenhouse Gasses will lessen the warming of the planet, and allow the atmosphere to stabilize. Melting of ice will decrease, and so the sea level will remain constant instead of rising. Impact on plants and animals will also be felt, as species that receded in the face of industrialization return to their former habitats, and forested areas can be replanted easier.
Regardless of the method used, curbing use of petroleum-based fuels is the only way to decrease gas emissions into the atmosphere. By making public transport safer, faster, and more efficient, people can keep to their busy schedules without overuse of resources, and the subsequent impact on climate change should be significant.