(Refiles to clarify attribution in paragraph two)
By Mark Tay
SINGAPORE, March 21 (Reuters) - Smoking costs the world 1 to 2 percent of its gross domestic product each year and could kill about 1 billion people this century, authors of the fourth edition of the Tobacco Atlas said at the book's launch in Singapore.
The economic losses include direct and indirect costs such as healthcare spending for treating smoking-related illnesses and the value of lost productivity, say the authors of the book, which is published by the American Cancer Society and World Lung Foundation.
The cost of smoking could be even greater, as co-author Hana Ross said it was difficult to measure intangible costs like the suffering of family members or pain felt by patients.
"During the 20th century, tobacco killed 100 million people. The estimate is that in the 21st century, tobacco will kill 1 billion people," lead author Michael Eriksen said at the launch of the book at a global health conference in Singapore.
The world's population has grown by more than four times in the last century, passing the 7 billion mark last year.
Eriksen said there are about 1 billion tobacco users around the world and 600,000 non-smokers die each year because of exposure to second-hand smoke - 75 percent of them women and children.
China is by far the world's largest consumer of cigarettes, with 38 percent of them in 2009, and saw costs due to smoking more than quadruple to $28.9 billion between 2000 and 2008, the authors said in the book.
"China has quite a problem because the tobacco industry is part of the government," co-author Judith Mackay said, noting that Beijing's move to raise tobacco taxes two years ago did not change the purchase price of cigarettes but merely manipulated the way taxes were paid to the government.
"China is in a process of change. It needs a little bit of the stick but quite a lot of encouragement to really take the process forward," Mackay said.
The world's most populous nation is one of the 174 countries to have signed and ratified the World Health Organisation's Framework Convention on Tobacco Control.
Some countries, including the United States and Argentina, have signed but not ratified, while Indonesia, Uzbekistan and Zimbabwe have done neither.
Eriksen described such treaties as "toothless".
"Any treaty is written by the member states who are the ones who are going to have to ratify it, so it is not in their interest to have penalties," he said.
"If you ratify and don't do anything, there is no financial penalty, which is wrong because there should be teeth. It is a life and death situation." (Editing by Robert Birsel and Jon Boyle)