At present, on our planets some scientist are talking about a climate change,this mean that the earth´s clime are changing by human activity. I think that nowadays this is a serious problems.Because our actions have polluted our planet. For example, our cars ejected very much carbon dioxide,which creates the atmosphere the greenhouse effect and this is the principal caused of climate change because of climate change the earth's temperature is increasing and the polar ice is disappearing. In conclusion; I think, this a problem... We could use our cars less and we can use the public transport, bike, skate... To move in the city. We need to be more ecological.