I second the AR5 report, and especially the Summary for Policymakers if anyone is curious about the effect of increasing temperatures, rising seas, ocean acidification, loss of crops, and the mass displacement of human populations. Of course, we are already seeing and living these changes, which were predicted long ago.
The simplest argument for human-caused global warming is that, mathematically, statistically, nothing else explains the temperature changes in the air and sea, the ice core data, the acidity changes, the mass dislocation of species, the melting of the glaciers, and so on. Nothing else explains the radically accelerating climate phenomena all around us except an aggravated greenhouse effect--aggravated from deforestation and fossil fuel use. This was first posited, in the english-speaking world, anyway, in the 1950's. I remember learning about global warming in the eighth grade. I think I remember being convinced around 1997 by a Nature article relating CO2 over Europe to temperature and crop changes.
Here's a simple graph of Sea Surface temperatures, that summarizes this kind of argument. You could build this kind of graph for many global phenomena, especially temperature phenomena.
This argument is very tough for people from religious backgrounds, though, because this kind of argument ("nothing else explains it") is usually used in theological catechisms to prove supernatural things--so it causes a lot of cognitive dissonance and many people with that kind of proof of God will listen to this kind of lecture and come away with the idea that God is heating the earth because the astronomical and other climate forces don't explain it.
Add to a supernatural belief in oil companies, like you have in my home state, and it's a simple but non-convincing argument to many people in a polity that matters a whole lot in the solution--the United States.
The United States profits immensely from oil and forest products export, so there are many companies that would lose if governments were to tackle the climate problem.
Forest products out of the Southern States, Georgia and Alabama come to the front of my mind. Oil was mostly out of Texas and Louisiana and the Gulf, but now Wyoming and the west have bought in. People and Governments would rather deal with the dislocation from all the flooding than deal with confronting these companies politically (although that is changing slowly).
It has been very disturbing to read these reports, to study the climate, to study the predictions of how societies crumble in the face of accelerating climate instability, and then watch it happen in the past decade. At this point, I recommend skipping the physics (WG1) to the results (WG2) sections of the different regions, so you can prepare for what it happening to the food supply and the populations dislocated in your region of the planet. Here's the one for North America.
If you'd like to learn about the psychology of denial, that's not something that the AR5 report is very good at; but it's a very real part of the problem. It's a problem that human society would rather deny responsibility to natural causes and ascribe terrible loss of life and material comfort to the supernatural or other people, forces beyond their control.
When people start to recognize that there is a human role in the problem, there's usually multiple attempts to deflect responsibility onto people less powerful in human society--witness the ecologist Hardin placing the burden of the problems of human population expansion onto poorer developing nations. The UN has been able to mitigate that crisis somewhat, and population is slowing down. Smarter heads prevailed, and through study, we've identified that the "population bomb" is really a global technological and societal problem--we need less impactful technology and more, dignity, health, and education for women to slow birth rates. But that took decades of unpacking and negotiating and the global solution we have is a bit unsatisfying--and solution didn't have very powerful oil companies campaigning against it.
And many people who do recognize the problem and think there's a solution get caught up in consumerist solutions--like, we all need to recycle or eat locally or buy CFL light bulbs, because they are afraid of disruptions in their economic security.
But what's sad is that those disruptions are coming anyway, unless we can act at the local and national political levels. This leads to despair. We've definitely seen that in Louisiana around the land loss issue--the forces that caused the problem are powerful enough to deny a solution decades after the science is in and the solution is clear, and even after a governing body (CPRA) has been convened specifically to deal with it.