“Climate change adaptation” is a term that is thrown around a lot in research and management circles. Although it is a relatively new, and sometimes daunting, term it can often refer to the thoughtful repurposing of management strategies. A prime example of this is the use of thin layer sediment augmentation in tidal marshes. Thin layer sediment augmentation (hereafter sediment augmentation) refers to the practice of spraying a slurry of dredge spoils and water from a barge or a system of pipes onto a marsh surface. As discussed in a previous post (link), marsh habitats are dependent on a balance between processes that increase and decrease marsh elevation relative to sea-level. Marsh elevation increases as a function of deposition of sediment from external sources (i.e. rivers), and plant growth. Elevation decreases due to decomposition of organic matter (plants), erosion, compaction, and sea-level rise. Local tectonics can also cause an increase or a decrease in elevation. Thus, thin layer sediment augmentation artificially increases the amount of sediment deposited on the marsh surface. In a typical marsh, annual sediment inputs are measured at a scale of millimeters a year. Sediment augmentation artificially increases the amount of sediment deposited on a marsh, by up to 60 cm. Excitement is growing in the natural resource management communities about the potential of using sediment augmentation as a climate change adaption strategy.
California forests give us clean water, clean air, wildlife habitat, lumber and recreation. But they are threatened by a maelstrom of environmental drivers of change, which have intensified across four years of drought. Consider just one indicator of forest health: In its most recent survey (May), the US Forest service said more than 12 million trees in California were dead. A scientist using new technology to measure drought stress said this week to the number may soar to 120 million — one-fifth of the state's forests.
We need a new vision for managing our wildlands with policies based on science and acting in the interest of the greatest public good. Horrific recent events should inspire reform of not only wildfire management, but also of our overall forest-health stewardship and governance.
The incentives -- and opportunities -- for real progress have never been greater. Federal agencies (which manage 19 million acres, or 57 percent, of California forests) have a new National Cohesive Wildland Fire Management Plan. The U.S. Forest Service is writing nearly 150 new fire plans. The top officials of the departments of Interior and Agriculture and of the White House Office of Management and Budget recently asked Congress to adequately fund the soaring costs of wildfire suppression (an estimated half of the USFS budget in 2015), so that they can stop borrowing from agency budgets for fire prevention, forest research and recreation.
…I’m just not sure we’re focused on the right sources of uncertainty. I spent the beginning of this week at the Southwest Climate Summit in Sacramento. The conversation among the scientists, natural resource managers, and bureaucrats inevitably turned towards uncertainty. I say inevitably because in my work with the Southwest Climate Science Center I often hear that climate models are “just too uncertain to be useful”. This seems reasonable. After all, there are at least 30 different models that describe our best estimate of how future climate will look (or feel)*. If one of these models was “right”, wouldn’t we simply get rid of the other models? Some of the models predict a warmer, wetter future – others predict a warmer, drier future. How do we know which model to believe? These are challenging questions to answer (especially for someone who is not a climate modeler), so I’m not going to try. I’m also not going to try because I don’t think these questions are the real roadblock to our collective ability to begin taking actions to plan for a warmer future**. I say this because making decisions under uncertainty is normal and because we are actually not that uncertain about how warm the future will be.
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