A favorite trick of scammers is to pick a phrase that is widely used and then use it to draw in site visits via Google searches for that phrase.1
If you search for "global warming scam" you will likely find a search result "global warming scam exposed". The site is earthpro.info and you will find a complete piece of BS that starts off with:
Global Warming Is A Total Scam
COMMENTS ABOUT GLOBAL WARMING
By John Coleman
it is the greatest scam in history. I am amazed, appalled and highly offended by it. Global Warming; It is a SCAM.
But that article is not what I am complaining about.
Regardless of my thoughts and feelings about global warming skeptics in general, I must be fair and say that I doubt very much if John Coleman wrote that article for that site, or is even aware of it.
The site earthpro.info is a commercial site specifically set up to make money. They will sell you tooth whitener, payday loans or even a perpetual motion machine. I kid you not.
If you go to the site earthpro.info you will see various ads. If you go there via a Google search, click the 'back' button. If you have opened the site in a new browser tab, close the tab.
A browser exploit will intercept your mouse click and throw up a dialog box. I hate those things. They intercept all mouse clicks and are very annoying. Click 'cancel'. You will then be presented with an advertisment for the Magniwork free energy device.
How would you like to create a generator which creates free electric energy? Using our easy-to-follow guide, you will be able create a Magnetic Power Generator which creates absolutely free energy, and doesn't require any resource like wind or solar energy to function, the magniwork generator creates energy by itself and powers your home for free.
This method has been researched for a long time, but due to suppression of this idea from the big corporations, the plans for building a free energy generator which could change the world have never been out on the open. We finally succeeded in creating a web site which offers the Do-It-Yourself instructions for building such a device, and it is considered that this device will be able to solve the energy crisis.
A Zero point magnetic power generator is basically a Free Energy Generator. It uses magnets, and magnetic force to induce perpetual motion. It runs by itself, indefinitely without stopping, thus creating completely free electrical energy, which can fully power your home for free. A Perpetual motion device refers to a machine that runs perpetually i.e. indefinitely, and produces a larger amount of energy than it consumes. Thus, it produces free energy indefinitely, runs by itself, without having to need a third-party device or resource to power it.
The free energy devices have been suppressed by the corporate world, because such devices, would allow people to create their own energy for free, which would ultimately shut down the big energy corporations, because people won't need to pay anymore for electricity to fill their pockets.
So there you have it: global warming is a scam because some guy named Paul Colcleasure says so, and he should know since he is an expert on the laws of thermodynamics. Not!
To paraphrase John Coleman: Perpetual motion - it is the greatest scam in history. I am amazed, appalled and highly offended by it.
 - When I use a phrase in such a way, it's called a 'hook headline', and is not at all unethical. ;-)