1997 will be remembered as the year the world caught fire, says the World Wide Fund for Nature. It says that in Indonesia and Brazil alone, fires devastated five million hectares - an area the size of Switzerland.

Although the fires in Indonesia grabbed the headlines, the fund points out that massive fires raged on every continent. For example, it says that forest fires increased in Brazil by 50% since 1996.

In some countries the impact of the fires was made worse by prolonged drought, exacerbated by the El Nino weather pattern. So-called greenhouse gasses released from the fires may in turn have contributed to the increased severity of El Nino, producing what the fund describes as a vicious cycle of destruction.

The environmental group quotes figures which it says show that peat bog fires in Indonesia in the next six months could release more carbon dioxide into the atmosphere than the combined annual production of cars and power stations in western Europe. The World Wide Fund for Nature says that many of the forest fires are set deliberately, and often illegally, in order to clear land for planting or development, or to cover up illegal logging.

It's called for the strict enforcement of national laws controlling forest fires and the introduction of new laws where necessary. The fund wants improved management of the world's forests.