Our climate has been subject to dramatic change over the last 150 years, we know this due to observing many variables in the climate system such as recording temperature. This is not just due to natural variations in the climate system, but also due to anthropogenic emissions of greenhouse gasses like carbon dioxide.
I am currently studying an online course on Climate Change from the University of Exeter, facilitated by Future Learn. Future Learn offers a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life. Oh and did I mention it is completely free? I recommend them, if you have a thirst for learning, you should check them out.