California state government and many local agencies put a premium on reducing greenhouse gas emissions that contribute to climate change. But recent developments underscore the parallel emphasis on adapting to the effects of global warming — from advances in sea-level rise strategies to stretching water supplies to thinning forests at high risk for wildfire. The scientific consensus that global warming is an existential threat is facing renewed challenge, especially with skeptic-in-chief Donald Trump taking up residence in the White House again next month. Regardless of what one thinks about climate change, it’s a fact that the seas are rising, wildfires are more intense and drought-afflicted water supplies are shrinking. Like efforts to slow or reverse climate change, projects to adapt to it aren’t cheap. But in many cases, not making the investments can be more expensive. The Pacific Ocean encroachment along the coast has triggered concern about serious environmental, health and economic problems, particularly for tourist economies. The city of San Diego is moving toward a long-term plan to deal with sea-level rise with natural dunes and earthen dikes instead of more intrusive projects of yesteryear, such as seawalls and culverts, according to David Garrick of The San Diego Union-Tribune. At the moment, San Diego is considering natural buffers in vulnerable areas such as La Jolla Shores, Tourmaline Surf Park in Pacific Beach, Mission Beach, Ocean Beach and Sunset Cliffs. The San Diego City Council is expected to review still-emerging plans in the spring. Oceanside is a step ahead, with its City Council last month approving a plan to replenish beaches and protect them from further erosion. The concept would rely on constructing natural headlands and an offshore artificial reef to dissipate beach-stealing swells, wrote the Union-Tribune’s Phil Diehl. These and efforts like them up and down the coast are gaining widespread interest, but they come with considerable uncertainty. Funding, naturally, is a big question mark. Cities would seek state and federal funds. But the local jurisdictions also will need to come up with money, which may not be easy for some. The city of San Diego, for instance, faces a five-year, $1 billion budget deficit. Meanwhile, there are fears that these coastal enhancements could increase erosion in nearby communities. Oceanside officials have been working with counterparts from smaller cities to the south to try to find a mutually beneficial way forward. Ambitious as these regional projects may be, they are not in the same league as what’s being attempted in the San Francisco Bay Area. The Bay Conservation and Development Commission voted unanimously on Dec. 5 for a plan to protect the more than 400 miles of bay shoreline from sea-level rise, which eventually could submerge portions of freeways, airports, rail lines and neighborhoods. Major hurdles abound. More than 50 cities and counties in the Bay Area need to get behind the plan, KQED reported. Then there are the state and federal approvals all these projects likely will require. State regulators estimate the Bay Area plan will cost $110 billion to construct all the seawalls, levees, marshes and other adaptation projects. But they forecast doing nothing would cost $230 billion. The threat is not theoretical. Garrick wrote that sea levels in San Diego have risen by about 6 inches since 1970 and are anticipated to rise another 9.6 inches by 2050, city officials said. By 2100, sea levels could rise 1.6 feet to 6.7 feet more, they said. The state’s potable water supply is going in the other direction. Gov. Gavin Newsom believes part of the solution to increasing drought risk is a tunnel to help move water south through the Sacramento-San Joaquin River Delta. That $20 billion, 45-mile project, officially known as the Delta Conveyance Project, received a boost earlier this month when the Metropolitan Water District of Southern California agreed to spend $141 million on planning costs for the proposal. Four Metropolitan board delegates representing the San Diego County Water Authority joined in the nearly unanimous vote to provide the funds, according to SDCWA spokesperson Mike Lee. Some sort of delta conveyance plan has been discussed for decades, but supporters believe its importance has grown with the effects of climate change on water availability in California. Newsom called the tunnel “the most important climate adaptation project in the United States of America.” He maintains the project is also needed to guard against possible water delivery disruptions caused by earthquakes. Disputes over water have been central to California history, with delta projects a big part of that in recent generations. Among other things, critics say conservation, recycling and local storage should take precedence over this proposal. Newsom and supporters say they are part of the mix but the delta system is needed for the state’s long-term future. On the wildfire front, members of Congress – including Rep. Scott Peters, D-San Diego – have been pushing legislation to increase forest thinning.  More is needed. Ron Nehring went so far as to accuse California officials of using climate change as a “scapegoat” for past wrongheaded policies and inaction. Nehring, the former chair of the San Diego and California Republican parties, served on the California Board of Forestry and Fire Protection in 2005-06 under Gov. Arnold Schwarzenegger. Nehring argued in the Flash Report that forest thinning has been too little, failure to create fire breaks and other community defenses have further exacerbated fire threat, and relying on remote solar and wind farms require long transmission lines, which can potentially start fires in the backcountry. The Breakthrough Institute, an environmental research center in Berkeley, noted California has committed to controlled burning of 1 million acres per year — but that the actual acreage burned has been far less. The institute’s Patrick Brown says what needs to be done to lessen wildfires is controlled burns of nearly 4 million acres annually. According to his analysis, that would cost some $10 billion each year — but he contends the statewide benefit would be more than double that.