No one can dispute that we are experiencing global warming, we have definite proof of this:

"Global sea levels are rising. They have risen about 400 feet since the earth emerged from the last Ice Age 20,000 years ago. Rising sea levels are a natural phenomenon during interglacial periods (the times between ice ages). However, much more is unknown than is known about what impact global warming would have on sea levels. The forecasts of future sea level changes, based on climate models, fluctuate wildly. In addition, scientists find it difficult to measure actual sea level rise accurately. And sea levels don't rise uniformly the world over.

Estimates vs. Observations of Sea Level Changes. Coming out of the Ice Age, sea levels rose at an annual rate varying from 1/16 to 8/16 inches [see the table]. Over the last 7,500 years the rate has averaged 1/16 inch per year. The most recent report of the Intergovernmental Panel on Climate Change (IPCC) noted that there is no evidence of an acceleration in the rate of sea level rise over the past century. "
http://www.ncpa.org/ba/ba282.html

Let me emphais the above point: over the last 7,500 years *on average* there has been 1/16" rise in sea level.
Now, without any human existing on this planet, we could actually expect a slight increase over the 1/16" per year at this time period. This increase could be expected because we still coming out of the "Little Ice Age".
"The Little Ice Age (LIA) was a period of cooling lasting approximately from the mid-14th to the mid-19th centuries. This cooling brought an end to an unusually warm era known as the Medieval climate optimum."
http://en.wikipedia.org/wiki/Little_Ice_Age

BUT we haven't been able to detect more than 1/16th per year for the last hundred years.
Continuing with excerpts from first article:
"Forecasts for the Next 100 Years. Forecasts for temperature increases over the next 100 years, based on climate models, have fallen over time. So too have forecasts for sea level rise.

In the early 1980s forecasters were predicting a 100-year sea level rise of 23 to 26 feet.

By 1990 the predicted rise was less than three feet.

Current IPCC forecasts are for a rise of about 1 1/2 feet, and other forecasts are lower [see the Figure]. "

Now what is 100 years times 1/16"? 6.25 inches. So IPCC is predicting about 3 times the average increase rate. Now if the increase was twice the average, it still wouldn't be surprising, it wouldn't mean that humans were causing it,- afterall we are coming out of the Little Ice Age. BUT we haven't even seen a doubling of this sea level rise.

Now, I am quite aware that Human activity (cities and urban areas) causes a heat island affect [this can increase average temperature in the local region by a couple of degrees in average temperature]. Can you show me data that allows for this heat island affect AND shows that the actual global temperature are being affecting by human activity?