Climate change is a reality and it is caused by the human race. Proof of its impact is already available and we must take steps to counter it. Cities are especially vulnerable, as most of the world's population lives in them, and they are the places where energy is consumed most intensively, generating 70% of all greenhouse gas emissions.
Climate change is a change in Earth’s temperature globally. Throughout history there have been natural changes and evolutions, but in the last few centuries data from around the world shows us that human activity has caused changes in the Earth’s climate as a consequence of emitting greenhouse gases into the atmosphere. This is a situation that poses a threat to the composition of natural ecosystems, their ability to recover and their productivity, economic and social development, and the health and wellbeing of citizens.
The greenhouse effect is a natural phenomenon. Part of the sun’s energy passes through the atmosphere and warms up the planet. This heat is retained thanks to a series of gases that absorb it. Climate change occurs as a consequence of human actions, when the amount of these greenhouse gases increases, meaning that more heat is retained than it would be naturally, increasing the Earth’s temperature.
Source: the energy rucksack and the Generalitat’s Climate Change website