From the video of David Suzuki, he mentions the Intergovernmental Panel for Climate Change (IPCC) report. According to their mandate on their website, they do not do research, observe or parameters to data. Rather, they are to assess the latest scientific, technical, and socio-economic literature worldwide in regards to climate change.
In an article by Nature (http://www.nature.com/climate/2007/0707/full/climate.2007.22.html), a scientific journal for the Nature Publishing Group (NPG),
it talks about how IPCC are quick to blame climate change is attributed by human activity and how the 2007 report specifically is a departure from earlier reports.
The report claims that the current change in global surface temperature due to CO2 is approximately 3ºC, which is the same as the US National Research Council panel said in 1979.
The article also talk about the reports using "uncertainty estimates" can lead to uncertainty global climate model calculations. The report has multiple runs of the climate models with modeled temperatures results that basically "gives a false sense of certainty that [is] achieved."
Alright I have written too much already.
What I basically want to say is that it is terrible that the scientific research has become more or less biased or even political. Depending on which media you go to, they have their own assumptions and "evidence" for it. It is sad when with research regarding global warming now, there's not one answer.