Holding a 20-foot rod Saturday next to a large inflated model of earth that appeared as if fire were engulfing its southern hemisphere, John Van Leer issued a warning.
''If we melt Greenland, I'm sorry to say this stick isn't long enough to touch where the water would rise to,'' he told a crowd of about 100 gathered in Peacock Park.
The message of Van Leer, an associate professor of Meteorology and Physical Oceanography at the University of Miami, was just one of several topics touched on during Environment Florida's clean energy rally in Coconut Grove.
The event was organized to warn about global warming, advocate for alternative energy sources and encourage people to reduce their carbon footprints, said Courtney Brigham, campaign organizer for Environment Florida's Clean Energy Now campaign.
Van Leer said because of global warming, streams of melting ice are now flowing off Greenland and into the ocean at an increasingly fast rate.
Scientists are still studying the huge mass of arctic islands to determine the effects of its melting ice caps.
Van Leer wasn't saying Peacock Park will be underwater tomorrow, but he urged that something has to change to stave off global warming.
Other warnings were issued Saturday, but much of the discussion was about encouraging state legislators to encourage the development of alternative energies, such as solar and wind power.
The crowd applauded state representatives such as Democrat Ron Klein and Republican Ileana Ros-Lehtinen for signing a commitment to push for clean energy and legislation that would curb global warming.
State Rep. Oscar Braynon, D-Miami Gardens, told the crowd that clean energy is what the state should emphasize.
''This is where we really need to concentrate,'' he said. ``We talk about it, but what are we really doing about it? The state needs to step up.''
Braynon said he planned to meet with Florida Power & Light this week to discuss clean energy production.
Others talked about creating green jobs, constructing green homes, and encouraging modes of transportation outside of motor vehicles.
The event was attended by Critical Mass Miami, a bicycling advocacy group, members of labor unions who want to encourage green jobs and development, faith-based organizations and City Commissioner Marc Sarnoff.
Mark Schaunaman, of the Operating Engineers Local 487, a heavy machinery operators union, said he came because he cares about green development.
''I want to promote green buildings and renewable energy,'' he said.
After the rally, some went to GreenStreet Café for a discussion on the world and energy, while others chose to hang around Peacock Park and hold their own debates.
Elizabeth Taveras, 18, said teenagers don't know enough about what is happening, but Asha Saluja, 17, said that's not the case.
''Everyone is concerned but not a lot of people are active,'' she said. ``No one is oblivious.''