Greenhouse gases are harmful gases that cause global warming, this is what most people know of greenhouse gases. Indeed their role in global warming phenomenon is their most important role, and unfortunately the biggest ecological problem we are facing today. Greenhouse gases are causing so called "greenhouse effect". Our planet gets plenty of radiation from the Sun that passes through the atmosphere to the Earth's surface where it gets released back into the atmosphere as Infrared radiation, of which some is absorbed by greenhouse gases. Greenhouse gases then return this energy in form of heat back towards the Earth.The higher the level of greenhouse gases in the atmosphere the more radiation is absorbed causing in the end higher temperature. Greenhouse gases are very important and play crucial role in maintaining the temperature of the Earth, without them life on Earth wouldn't be possible because planet would be too cold.
There is no doubt that we need greenhouse gases but the problem is in their current levels. Greenhouse gas that is getting lot of attention lately is carbon dioxide (CO2), among other more known greenhouse gases are methane and water vapor. Higher concentration of greenhouse gases in the atmosphere (most notably CO2) is the main cause why today we talk so much about global warming and climate change, and why Earth's temperature in the last 100 years increased by about 0,8 °C. As the levels of greenhouse gases in the atmosphere continue to rise so will the temperatures creating completely new conditions that will make life much more difficult than we can imagine.
With higher concentration of greenhouse gases in the atmosphere, and higher global temperature on our planet there will be a lot of problems that will present threat to entire life on our planet. Warmer temperatures will cause sea level to rise, which will lead to increased intensity of extreme weather events known as the climate change. Climate and weather will become totally unpredictable with frequent storms, hurricanes, floods and droughts. Many animals will go extinct and there is also the increased possibility of new diseases because of different Earth's climate.
Because of these reasons world is rightly worried about upcoming years, and if we fail to cut current levels of greenhouse gases emissions, future generations will suffer dearly. Scientists still do not have unique opinion what is the danger level zone of greenhouse gases in the atmosphere. Atmospheric CO2 is currently somewhere about 385 parts per million (ppm) and is increasing by about 2 ppm each year mainly because of fossil fuels burning. Some say dangerous level will start somewhere around 450 ppm or even higher, others say we have already entered the danger zone once we crossed the 350 ppm mark. But they all agree that we must cut greenhouse gas emissions as quickly as possible in order to have any chance against global warming. Infamous Kyoto protocol tried to make the difference but it failed at the very beginning by giving exceptions and not including major emitting countries like United States and China. The new agreement will have to include all countries worldwide with the special emphasis on major emitters and their reducing targets.
So now we know we have to reduce greenhouse gases emissions but the question how still remains. As long as fossil fuels (coal, oil) remain dominant energy source this doesn't look likely because fossil fuels when burn release large quantities of CO2 that ends up in the atmosphere. So we definitely need to turn our attention to renewable energy sector that is so far still negligible on global scale, still lacking in funds to become fully competitive with dominant fossil fuels. Development of renewable energy sector is still too slow, and still not economically acceptable (when compared to cheap fossil fuels like coal) to really make the difference. Power plants and vehicles are doing the most damage, and world will be forced to find the balance between economic and energy needs on one side, and environmental needs on other. This time on, environment needs to win.