"Taxes amounting to just 1% of world GDP would raise over $400 billion per year. Such a sum would meet many urgent needs while placing a very modest burden on the world’s richest consumers. Advocates have offered dozens of proposals for global taxes, but two have gained special attention: a tax on the carbon content of commercial fuels (often called a Carbon Tax), as a means to stop global warming, and a currency transaction tax (often referred to as a Tobin Tax), to reduce speculation and global economic instability." (Quoted from paper)