The myth "it's not us", skeptics believe that the Earth has been warming since the little ice age. Some factors that prove that we effect global warming are humans emitting around 30 billion tonnes of CO2 into the atmosphere, oxygen levels are falling as if carbon is being burned to create carbon dioxide, and corals show that fossil carbon has recently risen. Also two factors show that CO2 is trapping more heat are satellites are measuring less heat escaping to space at the precise wavelengths which CO2 is absorbed. Surface measurements find this heat is returning to Earth to warm the surface. An increased greenhouse effect would make nights warm faster than days, this was observed.
The myth "it's the ocean", states these small global temperature increases of the last 25 years and over the last century are likely natural changes that the glob has seen many times. Ocean circulation variations are yet little understood. The problem with the myth is that unless more heat was being poured into the oceans, they would be obliged by the laws of physics to cool when heat was transferred to the atmosphere. 80% of the heat in the ecosystem is stored in the oceans and have been consistently getting warmer over time. there would be other indicators such as the sea level remaining static or going down by small amounts.
http://www.skepticalscience.com/argument.php