Why yes, the globe is warming. There is tons of evidence indicating that over the last 400 years the average temperature of the earth has gone up. That same evidence seems to also indicate that the warming trend is unusual and is most likely having more of an impact due to the actions of humans on the planet. The most notable activity being the burning of fossil fuels. This information can be found in a report from the National Research Council, which was requested by Congress. http://darwin.nap.edu/openbook.php?record_id=11676&page=R1
There are many people today using the above information to take an alarmist stand and to create fear. However, if you read the report in it's entirety and not cherry pick the parts you want to support a presupposed point of view, the report presents other facts. Beyond the 400 year warming period there are some facts available about the last 900 years. Beyond 900 years, according to the report, the available data and methods for analyzing global temperatures are just not that certain. There are indications that the Earth moves through warming and cooling cycles every 100,000 years or so (Climate Change p. 5 Board on Atmospheric Sciences and Climate) .
There are also pundits that suggest we just don't know that much about climate change and we should study it more before we leap to any conclusions http://www.opinionjournal.com/extra/?id=110008597.
In any case, I believe that it is important for us to separate the Global Warming debate from good environmental stewardship. Whether or not you believe Global Warming exists or not, and whether or not you believe human behavior is having an impact, we should all strive to conserve resources and to be kind to mother Earth. For the foreseeable future, this is the only habitable rock we have to live on, so we better start taking better care of her.
##That's my opinion##