As climate continues to change, the biosphere is becoming more susceptible to environmental change. Those changes are disrupting natural ecosystem services, altering ecosystems, and placing strain on natural resource management strategies. As new and adaptive strategies are being formed in order to maintain ecological balance within ecosystems, many species and communities are altering their individual characteristics, their geographic ranges, and the timing of their natural biological events.

 Source: Chapter 7 of the Fourth National Climate Assessment



These maps show observed changes in timing of the start of spring over the period 1981–2010, as represented by (top) an index of first leaf date (the average date when leaves first appear on three indicator plants) and (bottom) an index of first bloom date (the average date when blossoms first appear on three indicator plants) {Source: Ault et al. 2015}.

All life on Earth, including humans, depends on the services that ecosystems provide, including food and materials, protection from extreme events, improved quality of water and air, and a wide range of cultural and aesthetic values. Such services are lost or compromised when the ecosystems that provide them cease to function effectively. Healthy ecosystems have two primary components: the species that live within them, and the interactions among species and their environment. Biodiversity and ecosystem services are intrinsically linked: biodiversity contributes to the processes that underpin ecosystem services; biodiversity can serve as an ecosystem service in and of itself (for example, genetic resources for drug development); and biodiversity constitutes an ecosystem good that is directly valued by humans (for example, appreciation for variety in its own right). Significant environmental change, such as climate change, poses risks to species, ecosystems, and the services that humans rely on. Consequently, identifying measures to minimize, cope with, or respond to the negative impacts of climate change is necessary to reduce biodiversity loss and to sustain ecosystem services (Source: Chapter 7 of the Fourth National Climate Assessment).

There are various changes happening in ecosystems, impacting plants, animals, and humans. Some of the most intense changes include changes in phenology or timing of biological events, changes in geographic range, and changes in primary productivity of photosynthetic organisms. These changes can influence the advancement of invasive species, which have been recognized as a major driver of biodiversity loss (Source: Chapter 7 of the Fourth National Climate Assessment).

Aside from these changes, the increased frequency of natural hazardous events are also impacting ecosystems and ecosystem services. Detectable changes in some classes of flood frequency have occurred in parts of the United States and are a mix of increases and decreases. Extreme precipitation, one of the controlling factors in flood statistics, is observed to have generally increased and is projected to continue to do so across the United States in a warming atmosphere. However, formal attribution approaches have not established a significant connection of increased riverine flooding to human-induced climate change, and the timing of any emergence of a future detectable anthropogenic change in flooding is unclear. Recent droughts and associated heat waves have also reached record intensity in some regions of the United States; however, by geographical scale and duration, the Dust Bowl era of the 1930s remains the benchmark drought and extreme heat event in the historical record. While by some measures drought has decreased over much of the continental United States in association with long-term increases in precipitation, neither the precipitation increases nor inferred drought decreases have been confidently attributed to anthropogenic forcing (Source: Chapter 8 of the Climate Science Special Report).

Guiding Concepts
  1. Help communities and natural resource managers determine if they are currently at risk from wildfires and if they will be impacted in the future due to wildfires becoming more prevalent and severe.
  2. Provide information to the public on their sources of water and their sensitivities to climate change.
  3. Aid in the public understanding of the role that ecosystems play in mitigating rising carbon dioxide levels due to their absorbing and storing of carbon, as well as how land management activities may influence storage capabilities.
  4. Identify the potential impacts of climate change on rare and endangered species, iconic species, and ecosystems.
  5. Identify which invasive species may threaten specific locations and their impacts on local communities and their economies. This effort will contribute to early detection, rapid response activities.

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Updated on April 21, 2021