When protesters seek to call attention to global problems, they often go to extremes.

Occasionally people take off their clothes and take to the streets to protest climate change and environmental degradation and to demand actions to reduce greenhouse gas emissions.

People protest naked, or almost naked, in an effort to create a media sensation and attract attention to their message. The naked body also sends a message that human beings are weak, vulnerable and insignificant in the face of powerful forces of nature.

The notion that mankind is vulnerable to Mother Nature has been expressed by philosophers for many years. Standing at the ocean or gazing up into the night sky, one is overwhelmed by a feeling of insignificance.

In a Greenpeace climate change protest in August 2007, 600 men marched naked in the Swiss Alps (good thing it wasn't winter).

They also called attention to the melting Alpine glaciers, which are diminishing in size because of global warming.

When the planet faces an emergency, etiquette goes out the window.

But an incident on August 5 in Shenzhen, Guangdong Province, was a cheap publicity stunt, a naked appeal for attention by 13 university girls who shed clothes down to tank tops and short-shorts (no big deal) in a subway car.

They said they aimed to promote awareness of global warming in the steaming subway system. Acting simultaneously, they stripped down to shorts, common attire nowadays.

The only reason it might be worthy of note was that the young women appeared to be performing a show. They did show a lot of leg.

Many critics condemned the action as "peddling porn," and an offensive demonstration of low-class values.

What's the connection between short pants and global warming? None. If they had draped themselves leaves, the message might have been more effective (and enticing). Organizers obviously wanted a bit of media attention for the silly catwalk show.

Commuters are used to seeing weird people and performers on the subway, so the girls' strip-tease didn't carry much environmental heft. They were just another bizarre sight on the subway.

If they really wanted to take it off, they should have gone to a rainforest.

(The author is an Australian student now living and studying in Shanghai. The views are his own.)