Hawai'i has some advantages over other areas when it comes to climate change, but the state's native forest bird and coral reef populations could be severely damaged, a climate change biologist said this week.

Conservation International scientist Lee Hannah said that while projected temperature change in Hawai'i is less than elsewhere, native species could still suffer from climate change.

But he also said extinctions of species in Hawai'i and around the world are not inevitable and that policymakers need to limit greenhouse gas emissions and improve conservation strategies.

"It's certainly not a case where all is lost," he said. "Climate change is another factor, and we need to respond to it, but it's certainly not a reason to give up hope because we have good conservation tools. We just need to employ them in ways that take climate change into account."

Hannah was among the scientists who spoke at this week's Forum on Climate Change in Hawai'i, which was sponsored by the Hawai'i Conservation Alliance, U.S. Fish and Wildlife Service and the U.S. Geological Survey.

Hannah said there is some good news for Hawai'i relative to other areas around the world. For example, the change in temperature projected for Hawai'i and Polynesia is less than those projected for most continental areas, he said. He said Hawai'i's topography and characteristics of elevated areas — especially on the Big Island — also mean there would be relatively more area for species to move upslope to cooler temperatures.

Hawai'i also has steep drop-offs into deep water, which may also help reduce coral bleaching.

However, the "more complicated news," Hannah said, is that Hawai'i has very little natural habitat left and what remains is already at upper elevations.

He said native birds living in upper parts of the forest are at risk of extinction from climate change. Mosquitoes that spread disease like avian malaria do not infest higher elevations where there are cooler temperatures. But as temperatures warm, this refuge for the birds will gradually diminish, he said.

Many of these native birds are already endangered, "but climate change is certainly adding another straw in, and whether it's the straw that breaks the camel's back or not is what we have to determine with our conservation actions," Hannah said.

'DOUBLE WHAMMY'

Coral reefs also could suffer severe damage — although extinction isn't nearly as imminent as with forest birds — because they face "the double whammy" of warming waters leading to coral bleaching as well as ocean acidification, Hannah said. That's on top of current pressures on reefs, such as sedimentation and overfishing.

Scientists haven't seen much coral bleaching in the Islands, but "we just know that they're at risk because we're seeing this happening at reefs all around the world," Hannah said.

Other species are also at risk, including sea birds, which nest on low-lying areas and could be impacted by sea level rise.

But Hannah said extinctions are not inevitable and that policymakers need to address two areas.

First and foremost, Hannah said, greenhouse gas emissions need to be limited. Natural resource managers also need to improve conservation strategies. For example, managers may want to expand protected areas upslope on the Big Island, he said.

Conservation strategies need to take into account climate change that is going to occur because of the greenhouse gases already in the atmosphere, he said.

"But because no conservation strategy is going to be able to deal with unlimited large-scale change, we need to get climate change under control quickly as well," he said.

DIFFICULT ISSUES

Hannah said conservationists will face some very difficult issues.

"One of them is when do we step in and rescue species, and when do we step in and artificially translocate species," he said.

"My personal feeling is that people like to take care of things. ... I think there's going to be an overabundance of enthusiasm for translocating (species) and moving them before the science supports it.

"My personal take on this is we should be very cautious about translocating things. But equally certainly with the amount of human habitat degradation that exists, some things are going to need help getting from here to there.

"The one thing that is certain is that we're going to need to rethink our management strategies. Conditions in the future are going to be nothing like conditions in the past."