Being that the topic of climate change has been increasingly debated over the past years, it is important to know whether the information you are reading is from a credible source or not. Nowadays, two people can easily get into an argument about whether climate change is real or not, and that even includes respected politicians. However, if you have looked at credible sources, you will have plenty of evidence to back up your arguments. To find out if a source is valid or not, you can ask yourself the following questions:
1. Who is the author and does he/ she have enough experience in this field?
2. When was this written? (Sometimes sources can be very outdated, and you would want the most accurate source)
3. Where did the author get his / her information from? (They could have done independent research or you can look at the citations that they provided)
For example, to find out more information about a source that is often used, I evaluated NASA’s Global Climate Change (Vital Signs of the Planet) website, which provides articles, facts, solutions, etc., regarding climate change. NASA, which stands for National Aeronautics and Space Administration, was established in 1958 with the vision to “reach for new heights and reveal the unknown for the benefit of humankind.” NASA brings together astronauts, engineers, scientists, technicians, and so on, with valuable credentials and expertise in their fields. The Global Climate Change website was specifically designed to provide information for the public about climate change. A lot of the information used by scientists comes from space satellites, information provided by scientists, and photographic evidence, and various space missions. Some of the information that space observations are able to provide include “…solar activity, sea level rise, the temperature of the atmosphere and the oceans, the state of the ozone layer, air pollution, and changes in sea ice and land ice” (NASA).

Space earth-observing satellites
Since the people working for NASA have done substantial research and have provided a lot of evidence based on models, satellites, and space missions, you can say that their website is a very credible source.
Citation
Climate Change: Vital Signs of the Planet. (2017). Global Climate Change: History. [online] Available at: https://climate.nasa.gov/nasa_science/history/ [Accessed 25 Sep. 2017].