You could start with anthropogenic global warming. Most legitimate research refutes IPCC claims in that they consistently lack scientific rigor and fail in every prediction made to date. The whole IPCC propaganda machine will survive only as memory and an example of how science is not to be done - not the least of which is by a so called consensus which never existed. Just to name one example you might consider the 50 NASA scientist and astronauts who wrote:
“claims by NASA and GISS, that man-made carbon dioxide is having a catastrophic impact on global climate change are not substantiated, especially when considering thousands of years of empirical data. With hundreds of well-known climate scientists and tens of thousands of other scientists publicly declaring their disbelief in the catastrophic forecasts, coming particularly from the GISS leadership, it is clear that the science is NOT settled.”
Also, there is a new theory which explains the mechanism for ice age and hot house cycles which has been under the radar for about 15 years now in spite of research at CERN which confirmed that cosmic rays generate highly reflective earth cooling low level clouds.
The ‘hockey stick’ (a stupendously erroneous concoction) conveniently removed the medieval warm period from public attention in what was a blatant abuse of scientific privilege. The MWP did happen and Michael Mann or the IPCC, try as they might, cannot make it go away.
AGW is not about science. It is about money and lots of it! Anyone at the IPCC and many other university employees who value their job, but not necessarily their integrity, know that it is about money and to keep the gravy train rolling they must insist at all costs that AGW is real.