What kind of ecological damage
can result in torching the oil
fields in Iraq?

Except for the rate of use by burning and that nothing useful occurred as a result of the burning..just flat out waste.. the ultimate impact on the environment is about the same.
CO2 ,C0 is burned. Lack of efficiency will make for particulate smoke. And sulfer emissions will not be captured/controlled. But The basic chemistry is the same in an open air wasteful burn vs in someone's car on the way to the supermarket. We only get to use it one time either way.

Thank You, Peteeo!

This link might interest you. It's about the environmental impact of
iraq burning Kuwait's oil after the last gulf war.

The partially-burnt oil has serious effects on the atmosphere (causing/aggravating respiratory diseases and acid rain), unburnt oil gushed out of the ground and also affected the atmosphere, the tmperature and oil made the soil infertile, and oil was dumped into the Gulf.

Interesting, methos and
thanks for the link!