Likewise, construction responsible for global warming too. In the process of building, it requires a lot of raw materials such as concrete, woods, sand, etc. Wood is from tree and tree has a vital role in mitigating global warming. So they have a connection between deforestation and construction. Additionally, we are using air-conditioner, refrigerator, television more and more. It will increase the energy consumption. And ironically, we make electricity from fossil fuel. Construction also lead to a so-called “Embodied Energy”. For instance, woods that located in town will have lower embodied energy than woods from another city, because they have to drive further than in town. According to a study in 2009, 30% of gases emission is caused by building. It is the most contribution to global warming.Beside human activities, global warming can be affected by some natural activities. For example, permafrost, a frozen ground which contains plants and animals died since the last ice age, may contribute vast amounts of CO2 and CH4 if it leaks into the atmosphere. A study in 2015 predicted that the thawing permafrost could produce up to 92 gigatons of CO2. For your information, all people in the world just breath out 3000 million tons of CO2 a year. So, when the temperature climbs up enough degree, it will trigger permafrost to thaw. Permafrost currently covers about nearly 15 million km2. And scientists found if 6.5 million km2 of that thaw, the world temperature can increase to 2 degrees. Many species will extinct, some cities will disappear because of glacier melt. It is very horrible if that happened.In addition, unexpected events like forests fires also involved in global warming. In 1997, a forests fires occur in Indonesia emitted up to 2.5 gigatons greenhouse gases (equal to 40% of the size of global fossil fuel emissions). Scientists measure that from 1850 to 1980, 120 billion metric tons of CO2 were discharged into the atmosphere from forest fires. The damages from forests fires is from $650 million a year. Forests fires not only affect the air temperature but also affect the world economy.