Climate change is coming like a runaway freight train, bringing with it the triple blows of starvation, mass migration and war.
And Canadian journalist Gwynne Dyer fears the seemingly overwhelming impact is likely to be felt sooner than first feared.
Speaking to 500 people at the University of Otago in Dunedin last night, Mr Dyer pointed to the increasingly rapid melting of Arctic ocean ice as one example.
Forecasts had projected a complete loss of ocean ice during summer months by 2040, but evidence now suggested that could happened as soon as 2013.
"There's a sense of suppressed panic in the relevant scientific community now. Things are moving considerably faster than their models predicted," he said.
The implications for global order were likely to be catastrophic, ranging from dwindling food supplies as the world's food-producing regions turned to deserts, to mass starvation, migration and war.
Already there was increasingly hostile rhetoric between Canada and Russia over rival claims to resource-rich Arctic territory, and the threat of conflict between nuclear rivals India and Pakistan over dwindling water supplies.
Mr Dyer believed international efforts to cut emissions were unlikely to succeed in time to prevent average temperatures increasing by 2degC - a threshhold beyond which climate change could spiral out of control.
That left seemingly unpalatable geo-engineering initiatives as the only options to buy time, such as releasing sulphur dioxide into the atmosphere to block sunlight and control warming while emissions cuts continued.
Mr Dyer, whose columns on international affairs are published by more than 175 papers in 45 countries, has spent 18 months researching his new book Climate Wars.
