Skeptics argue,however, that rising temperatures and warmer oceans are part of a natural cycle and are not convinced the changes are a result of man's pollution.

VOA: standard.2009.05.03

Skeptics say global warming is part of a natural cycle of climate change.

VOA: standard.2009.12.09

Irons is part of a team with the Illinois Natural History Survey.

VOA: standard.2010.07.20

But the decision to hold most of the exercise in Kitgum has raised questions as to whether Natural Fire 10 is part of preparations for a renewed military effort against the Ugandan rebel group, the Lord's Resistance Army.

VOA: standard.2009.10.20