What does wildlife conservation mean to you? Setting aside land? Restoring habitat? Reducing local stresses to species or ecosystems? These are the conventional methods. But because of rapid climate change, scientists in a recent paper say this may not be enough:

[T]he future for many species and ecosystems is so bleak that assisted colonization might be their best chance.

Assisted colonization – moving species to sites where they aren't native – is a high-risk suggestion. There are many cases, for example, where introduced species have become invasive and wreaked havoc on native ecosystems. So why would some of the world's leading biologists make such a suggestion?

Moving Targets

Well, they're not recommending wholesale resettlement of Earth's species. They say that moving a species should be an option of last resort. As a first line of attack, traditional conservation efforts should be continued and improved. Also, land managers should improve wildlife corridors to facilitate unassisted colonization – plants and animals moving on their own to more favorable locales.

Long-term records show that plants and animals are already moving on their own to keep up with temperature changes, generally toward the poles or up in elevation. (In some cases, this can lead to some nasty surprises – for example, disease-carrying mosquitoes moving into areas they didn't previously inhabit.)

But unfortunately, many plants and animals can't move fast enough to survive. Routes to new habitat may be cut off by development, or they simply may have nowhere to go. A species living on a mountain, for example, only can move up so far before reaching the top.

It's in these situations that the scientists say assisted colonization should be considered. Here are their suggested criteria for identifying candidate species:

• High risk of decline or extinction due to climate change
• Move to new habitat is technically feasible
• Species cannot move to new habitats on their own
• Conservation benefits of moving outweigh potential costs

In some cases, there will be nowhere a species can go to survive. Then, the scientists say, storing frozen eggs, sperm, or seeds until suitable habitat can be found may be the only way to prevent extinction.

The fact that such a drastic recommendation is coming from leading biologists underscores the level of scientific concern about extinctions due to global warming. On the plus side, they think it's possible to move some species safely. At the very least, they've opened the door for an interesting discussion.

How do we plan for climate change? Unfortunately, many groups don't even ask that question, much less begin to answer it.

I'm happy to report that there are exceptions. Yesterday, I testified before the New York City Council's Infrastructure Task Force, which held a forum on how climate change and flooding will affect the city's infrastructure. It was an interesting experience. I left feeling cautiously optimistic that the city really is trying to tackle the problem.

The session included speakers from state and city agencies, universities, engineering firms, and non-profit organizations. Here are some of the highlights:

• Several professors and engineers described how rising sea levels, stronger storms, and greater storm surges could devastate the city's transportation and energy infrastructure. One speaker estimated that damage from a major hurricane hitting New York City could be as high as $1.9 trillion.
• I was pleased to learn that the state and city are already discussing how to adapt water and sewer systems to climate change. Their priorities include updating projections for sea-level rise and probable flood areas, and identifying the additional data and monitoring stations they'll need. They're also working to diversify the city's water supply, and increase conservation and watershed protection programs.
• Disaster managers, relief organizations and health specialists described how the city could improve its evacuation and response plans. They urged the city to consider "intangible infrastructure" such as health services.
• A Dutch engineering firm talked about storm surge barriers and other ways to protect urban areas from flooding. The Dutch have centuries of experience with this, because large parts of their country are below sea level. Prevention is their primary strategy. Holland is prepared for a "10,000 year storm" (a storm extreme enough to have only a 1 in 10,000 chance of occurring in any given year). In contrast, New York City is incredibly vulnerable to flooding from current storms, never mind the monster storm surges we could see in the future.

In my testimony, I highlighted the city's vulnerability to climate change and flooding, and recommended two important steps:

• Build resilience. With thoughtful leadership, New York City can lessen the risks and costs of climate change. For example, the city should revisit zoning and building codes with climate change in mind. Right now there is rapid development in low-lying areas that will be increasingly vulnerable to flooding. (Andy Darrell, Vice President for Living Cities at EDF, was only half kidding when he told me "the city should be issuing snorkels along with building permits".)
• Lead on solutions. New York City can set an example that influences national action on climate change. Some key steps will be adopting clean energy where possible, and making buildings more energy-efficient.

In my closing remarks, I urged the task force to move beyond the discussion and planning stages and into action. I'll be following their progress with interest.