The bad news? Climate change will bring floods, fires, droughts.

A draft report that's one of the first in the nation to boil global warming down to the local level says Southern Oregonians can expect hotter summers, more floods and droughts and larger wildfires in this century.

The Rogue Basin climate change study, to be released Monday, predicts searing summers with average dry season temperatures climbing 15 degrees by 2080. It also forecasts diminishing mountain snowpacks, meaning less water for summer stream flows.

There will be extreme wet cycles in winter and spring, causing more flooding, but that will be intermittently broken by extended droughts creating explosive wildfire potential in summer, the report says.

Many of the conifers now found in Jackson and Josephine counties will be replaced by madrone and oak trees, the study concludes.

"What we've found so far strongly suggests that local, state and federal agencies, as well as private companies and individual households, would benefit greatly by taking into account the risk and stress climate change will bring to the Rogue Basin," said Bob Doppelt, one of the authors of the report.

"They should begin to integrate those factors now in how they plan for the future. Activities taken today can make things worse, even in as little as 30 years. We need to consider what we are doing now to make sure it doesn't exacerbate the problem."

The study is the result of a collaborative effort by the Climate Leadership Initiative and the Institute for Sustainable Environment at the University of Oregon, the Ashland-based National Center for Conservation Science & Policy and the U.S. Forest Service Northwest Research lab in Corvallis. Doppelt is director of both the CLI and the U of O institute.

The report will be presented during a daylong workshop Monday at the Medford library specifically designed for local community leaders, land-use planners, emergency responders and others who will be asked to develop recommendations needed to prepare for global warming. Up to 50 people from the two counties have been invited to participate.

Recommendations from the workshop will be sent to the governor's new Oregon Global Warming Commission charged with helping to prepare the state for expected climate change.

After the Rogue Basin report is finalized, a process that will include vetting by peers in the scientific community, similar studies will be done on the effects of global warming on the Klamath River Basin in Oregon, the upper Willamette River drainage and the Umatilla River watershed. The goal is to find trends unique to the four sites, as well as similarities that can be applied statewide in developing preparation strategies for climate change, scientists say.

Three computer models employed in the Rogue Basin study are among the same ones used by the International Panel on Climate Change, a consortium of 2,500 scientists from 130 countries. The climate models focus on historic weather records, current data and changes on the ground.

The goal is to determine what local residents can expect with global warming, then prepare strategies to mitigate the weather extremes, explained Cindy Deacon Williams, a Medford resident and report author. The fisheries biologist is the senior scientist at the Ashland center.

"We are going to have to think creatively to prepare," she said. "We need to increase the ecological resilience on the landscape so the land will work with us to moderate the effects of flood and drought."

Like the other scientists, Williams encourages the reduction of greenhouse gases — carbon dioxide, methane, nitrous oxide — to decrease the impact of global warming.

But she likens that reduction to applying the brakes in a car — it will only slow down the accelerating warming process fueled by accumulated gases now in the atmosphere.

"Climate change is already under way — we are going to have significant changes in our climate," she said. "The preparation strategies we are coming up with now are like air bags in a car. They will help us absorb those changes."

Land-use planners, for instance, knowing the report predicts more flooding during wet cycles, can adjust regulations regarding building in floodplains, she said.

"Frankly, these predictions are a little bit scary when you step back and realize there are likely to be more floods, droughts and wildfires," she said. Preparing for the worst-case scenario can substantially mitigate the impact, she said.

The report localizes what the IPCC has concluded: Human reliance on carbon-based fossil fuels has caused most of the increase in global temperatures over the past 50 years. The IPCC's worst-case scenario projects that global temperatures on average will rise as much as 10 or 11 degrees in the next 100 years, making it the warmest period in the past half million years.

Scientists report the last half of the 20th century was dramatically warmer than the first half, corresponding with the increased use of fossil fuels along with increased deforestation and urbanization. Since 1990, U.S. greenhouse gas emissions have risen some 16 percent, they say.

While Doppelt and Williams observe the scientific community largely agrees that human-caused global warming is a problem, they concede the general population needs more convincing.

"Nationally, we see more and more people understand there is a problem but the understanding is only skin deep," Doppelt said. "There is still a core segment that really doesn't understand or flat out doesn't think there is a problem."

Perhaps changing the global warming moniker would bring more understanding, he offered.

"A better term for climate change is climate weirdness," he said, referring to fluctuating wet and dry cycles.

Contributing to the problem is the enormous complexity of the issue, Williams said. Looking at it from a local perspective, the Rogue Basin is in a transitional zone where weather patterns can fluctuate, she said.

"A non-scientist looking at the three models we used would see a fairly divergent precipitation prediction from one model to the next," she said, adding that person would see what appears to be an obvious conflict.

In fact, one model forecasts more rain locally while the other two predict a decrease.

"But a climate change expert looking at the three models from a broader view would say we will have both, including long wet periods, then a long drought," she said. "We will likely have all of that in the coming century."

The point, she said, is that while the climate is always changing, those changes appear to be accelerating because of the buildup of greenhouse gases.

"Our grandkids are the ones facing what the world will throw at us," she said. "We need to help them be prepared."

Southern Oregon University environmental studies professor Greg Jones, a climatologist who was one of the authors of the IPCC study released early last year in Paris, applauds the effort to localize a worldwide issue.

However, it is a challenge, given many who remain skeptical of the potential risks, he said.

"How we react to things in the environment in our daily lives is based on how we perceive those risks," he said. "When we normally talk about climate change, it's a slow process. A 1-degree increase in average temperatures doesn't mean much to people.

"Who cares at that point? It would just make it nicer at the beach," he added. "If we don't perceive the risk associated with small amounts of warming, how can we respond to it? People need to be aware there is a greater perceived risk from climate change."

Noting the urban-rural interface in Jackson and Josephine counties is one of the highest percentages in Oregon, Doppelt said the Rogue Basin is an ideal place to start a dialogue on the global issue.

"Our interest in doing this is to help local, state and federal government as well as private companies and organizations develop an understanding of what they can expect," he said. "We hope that Jackson and Josephine counties, as well as Medford and Grants Pass, then move from there to form a preparation strategy."

Reach reporter Paul Fattig at 776-4496 or e-mail him at pfattig@mailtribune.com.