I needed to think about this for a few minutes so I will do my best to keep it short and simple. It might take two post to complete my total thoughts.
My background: My family and friends live and work inside the environmental world and I am on the low end of the spectrum. So here goes, I have a degree in Psychology with a minor in chemistry. I followed a different path after I graduated and got into the printing industry. My father was an enviromental engineer, as well as my two brothers, one cousin is a nuclear physicist and another is a geologist, and one of my best friends has a degree in forestry and works for a logging company. I could go on.
Is Global Warming real?: Yes and No. The term Global Warming is, IMHO, a made up term to make us feel safe about a real condition, politcal not scientific. Like the term Post Dramatic War Syndrome, it used to be called Shell Shock. With Global Warming a better term would be an "Enviromental Imbalance". The earth is an ever changing, living thing and will continue to do so with or without our help. But it is this process of change that effects all of the living creatures on it.
What causes this imbalance?: (I hate this term too), Greenhouse gasses: Carbon Dioxide, Methane, the flouro. gasses, and Nitrious Oxide (human and animal waste so light a match ;D). The earth produces these gases naturally to keep itself healthy but when we add to them we are making the earth sick. We are destroying our protective shell (the Ozone Layer and yes, it is real) at a faster rate and it also changes the atmospheric temp. Which brings about, everyone favorite, the ICE AGE. This, IMHO, is what heals the earth and our ozone layer. I can't say for sure, I was not around for the last one.
How can I tell if it is effecting me and my fishing?: As fisherman we tan out in the sun. Think back twenty or so years ago. At least for me, I burn like crazy now. This is gray to me, but according to family, this is where the UV index comes in. Less ozone layer=crispy earth (sort of). When the ozone layer allows more UV, Xray and Gama rays in to the earth the ground temperature will rise but with less of an ozone layer we can't keep that heat locked in. Ask any saltwater fisherman, how the fishing has changed around the reefs which are older than some land masses.
The human race has changed the earth more in the a last 200 years than anyting has in the last 10,000. The earth needs to find a way to keep the balance in check and this will directly effect how we enjoy our sport. This again is just an opinion. I have had to retype this BS twice because my computer connection is bad so I am tired and feeling my age. 5 am comes early so I might continue this tomorrow when I can think straight.