The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) project concluded a yearlong expedition into the Arctic ice pack, collecting data that aims to advance understanding, modeling, and prediction of Arctic environmental change. Sea ice cover in the Arctic Ocean has shrunk dramatically over the past four decades as temperatures in the region have warmed at over twice the rate as the rest of the globe. This trend is expected to continue, resulting in nearly sea-ice free late summers in the Arctic by midcentury. 1 Arctic sea ice plays a key role in shaping climate...

A reconstruction of daily weather back to 1806 puts current climate trends into historical perspective. Historical weather reconstructions, or reanalyses, combine weather model output and observations from many sources to estimate the state of the atmosphere at a particular instant in time, over the entire globe. Reanalyses provide the context for understanding how weather and climate events and trends are changing over time and support improved prediction of future changes. An interagency partnership between NOAA and DOE supported an updated version of the 20th Century Reanalysis Project (...

A national system of physical, ecological, and societal indicators is considered a foundational component of the sustained assessment process, serving to help users understand the changing environment, assess risks and vulnerabilities, and make informed decisions to build resilience to change. A 2019 Federal–academic workshop sought to advance the development of socio-environmental systems indicators of climate change to support adaptation and resilience decisions at various scales in the United States. This work was supported by the National Socio-Environmental Synthesis Center (SESYNC) under...

Most regions of the United States are projected to experience a higher frequency of severe droughts and longer dry periods as a result of a warming climate. 1 In 2016, USDA Forest Service (USDA-FS) scientists and partners prepared a state-of-the-science synthesis of drought effects on the nation’s forests designed to inform drought resilience and adaptation efforts. A new volume released in 2019 builds on that work, linking recent scientific evidence with regionally focused discussions of risks, vulnerabilities, and management options to minimize drought impacts, optimize forest and rangeland...

Climate indicators show trends over time in key aspects of our environment, such as greenhouse gas levels in the atmosphere, temperatures across land and sea, and the extent of Arctic sea ice, as well as metrics of social or economic exposure to the impacts of climate variability and change. Indicators are based on long-term, consistently collected data and can be used to assess risks and vulnerabilities from a changing climate and to inform response actions. USGCRP’s Indicators Interagency Working Group (IndIWG) leverages existing agency research, data, and indicators in support of sustained...

Long-term measurements of Earth’s atmosphere show rapidly rising concentrations of greenhouse gases linked to human activities. 1 Existing observing networks provide information on atmospheric concentrations of greenhouse gases at the global scale, but this spatial scale is not sufficient to help nations, regions, and other entities quantify and manage greenhouse gas emissions. To improve the relevance of emissions information for decision-making, an international initiative is promoting scientific methods that combine atmospheric concentration and emissions inventory data with simulations of...

Fire risks to human health and property have increased in recent decades due to the impacts of a warmer, drier climate on ecosystems as well as historic land use and management practices. Smoke from wildfires in the western United States and agricultural fires in crop-producing regions such as the southeastern United States increasingly impacts air quality, with expected negative effects on human health. 1 The impacts of smoke on atmospheric conditions depend on many factors : the kind of fuel being burned, weather and climate conditions at ignition, and how smoke moves through the atmosphere...

Satellite observations show significant declines in Arctic sea ice cover in recent decades as the climate has warmed, 1 with impacts on fish and wildlife habitats that are important for subsistence, recreation, and tourist activities in the region. Retreating sea ice also contributes to increased storm surge, coastal flooding, and coastal erosion. 2 Arctic sea ice plays a key role in moderating climate within and beyond the region, and understanding sea ice change is critical to projections of future climate change. Complementary ground and remote sensing observations provide measurements of...

The U.S. Midwest is a major producer of a wide range of food and animal feed for national consumption and international trade. Higher humidity, precipitation, and temperatures associated with a changing climate increasingly impact agriculture in the region, and projected climate changes are expected to pose growing challenges to agricultural productivity in the coming decades. 1 Weather and climate information targeted to the needs of agricultural producers can help producers increase the resilience of their operations to climate variability and change. USDA’s Midwest Climate Hub works closely...

According to independent analyses by NASA and NOAA , Earth’s average global surface temperature in 2019 was the second warmest since modern record-keeping began in 1880. Globally, 2019’s average temperature was second only to that of 2016 and continued the planet’s long-term warming trend. Rising temperatures are contributing to glacier melt, disappearing snow cover, shrinking sea ice, rising sea level, and changes in rainfall patterns. 1 NOAA and NASA take slightly different, complementary approaches to interpreting global surface temperature, and work together to produce and communicate an...