Thirteen federal agencies and more than 300 experts, both from inside and outside government have been working for two years on the Fourth National Climate Assessment (NCA4), a report on the impacts …
Thirteen federal agencies and more than 300 experts, both from inside and outside government have been working for two years on the Fourth National Climate Assessment (NCA4), a report on the impacts of climate change on the United States and the world (www.globalchange.gov.) The production of the report is required by a law passed by Congress in 1990.
Many observers have speculated that the administration of President Donald Trump arranged to have the report released on Black Friday, the day after Thanksgiving, in an attempt to mute the dissemination of the contents of the report. Still, it was the topic of hundreds of news articles and has been widely quoted as saying that climate change is already here and having a significantly negative impact.
The assertion gaining the most attention perhaps is about the economic impact of continued burning of fossil fuels on climate change. NCA4 says, “With continued growth in emissions at historic rates, annual losses in some economic sectors are projected to reach hundreds of billions of dollars by the end of the century—more than the current gross domestic product (GDP) of many U.S. states.”
The 1,600-page report includes 10 chapters on the impacts of climate change in various regions of the U.S. The Upper Delaware is included in the Northeast Region which, for this report, extends from West Virginia to Maine.
The report notes that the Northeast has experienced a greater change in seasonal temperatures than any other region of the continental U.S. “Forests are already responding to the ongoing shift to a warmer climate,” according to the report, “and changes in the timing of leaf-out affect plant productivity, plant–animal interactions and other essential ecosystem processes. Warmer late-winter and early-spring temperatures in the Northeast have resulted in trends toward earlier leaf-out and blooming, including changes of 1.6 and 1.2 days per decade, respectively, for lilac and honeysuckle,” since the 1950s.
That could be good from some sectors of the agricultural industry, but the earlier spring also comes with challenges, especially for farmers who grow fruit. “Early emergence from winter dormancy causes plants to lose their tolerance to cold temperatures and risk damage by temperatures they would otherwise tolerate. Early budbreak followed by hard freezes has led to widespread loss of fruit crops and reduced seasonal growth of native tree species in the Northeast.”
The report further says that species that depend on a specific type of environment may face the risk of extinction. “Species that are particularly vulnerable to temperature and flow changes include stream invertebrates, freshwater mussels, amphibians, and coldwater fish. For example, a recent study of the habitat suitable for dragonflies and damselflies (species that are a good indicator of ecosystem health along rivers) in the Northeast… projected habitat declines of 45%–99% by 2080, depending on the species.”
The milder winters and earlier springs will also likely mean a range expansion and growing numbers of invasive and unwanted insects that damage native trees, such as, hemlock woolly adelgid, emerald ash borer and southern pine beetle.
The production of maple syrup over the long term may be in doubt for some regions in this area. Maple syrup production depends on a number of factors linked to the climate. Per the report, “Climate change is making sugar maple tapping more challenging by increasing variability within and between seasons. Research into how the industry can adapt to these changes is ongoing.”
Currently less precipitation falls in the form of snow in the region, and more in the form of rain compared with decades past. This trend is expected to continue and expand and poses a threat to skiing operations in the Northeast. “As the margin for an economically viable winter recreation season (a season with more than 100 days for skiing; more than 50 for snowmobiling) shifts northward and toward higher elevations, some affected areas will be able to extend their seasons with artificial snowmaking,” the report reads. “However, the capacity of some vulnerable southern and low-elevation locations to adapt in the long term is expected to be limited by warming nighttime temperatures.”
According to this report, there are many questions as to exactly how climate change will play out, but it leaves no doubt that it is already here and is unquestionably caused by human activity. “Global climate is changing rapidly compared to the pace of natural variations in climate that have occurred throughout Earth’s history. Global average temperature has increased by about 1.8°F from 1901 to 2016, and observational evidence does not support any credible natural explanations for this amount of warming; instead, the evidence consistently points to human activities, especially emissions of greenhouse or heat-trapping gases, as the dominant cause.”