Highlights

Since 1989, the U.S. Global Change Research Program (USGCRP) has submitted annual reports to Congress called Our Changing Planet. The reports describe the status of USGCRP research activities, provide progress updates, and document recent accomplishments.

In particular, Our Changing Planet highlights progress and accomplishments in interagency activities. These highlights represent the broad spectrum of USGCRP activities that extend from Earth system observations, modeling, and fundamental research through synthesis and assessment, decision support, education, and public engagement.

Regional comparisons of submarine (1958–1976 and 1993–1997), ICESat (2003–2007), and CryoSat-2 (2011–2016) ice thickness data, showing declines in ice thickness over time.

Satellite observations of sea ice thickness provide an opportunity to improve seasonal predictions of Arctic sea ice cover.

Arctic sea ice grows and melts each year with the seasons, reaching its low point in September. Summer sea ice cover has shrunk significantly over the past thirty years, although variation from year to year means that the downward trend is not uniform. Arctic sea ice plays a critical role in regulating weather and climate in and beyond the region. Sea ice decline activates a feedback loop in the climate system: as highly...

Map shows the average active layer thickness (ALT) at the end of the growing season for the Barrow, Alaska region that contains the NGEE Arctic study site.

Scientists are gaining new understanding of processes that control greenhouse gas emissions from Arctic permafrost, a potential driver of significant future warming.

Rapid warming in the Arctic is causing carbon-rich soils known as permafrost, previously frozen for millennia, to thaw. As thawing soils decompose, the greenhouse gases carbon dioxide and methane are released into the atmosphere in varying proportions depending on the conditions under which decomposition occurs. Permafrost emissions could contribute significantly to future warming...

Coordinated experiments run across major Earth system models help improve model projections and advance climate science understanding.

Projections of the future state of the Earth system can differ significantly across models, with various potential sources of uncertainty. To better understand the sources of difference and where fundamental scientific understanding can be improved, the Earth system modeling community uses a set of experiments run across many models known as the ...

Model runs of CMIP5 models without greenhouse gas forcing (orange lines) demonstrate natural variability in average annual global surface temperatures expected without human influence on the climate.

Earth system models allow researchers to evaluate the size and strength of various influences on the climate system and identify the human contribution to the warming trend.

Earth system models allow researchers to distinguish “internal” climate variability (natural climate cycles) from the effects of “external” influences on the climate, both human and natural (including variations in incoming solar energy, volcanic eruptions, and greenhouse gas emissions from human activities). Model simulations of natural variability from the...

Researchers found that reducing aerosol pollution can achieve both direct and indirect health benefits.

Atmospheric aerosols are tiny airborne particles that can dramatically affect the Earth’s climate through their influence on the flow of energy between Earth’s surface and space. Some aerosols have a cooling effect by reflecting solar energy back into space, while other aerosols containing substantial amounts of carbon warm their surroundings by absorbing the sun’s energy, and can also directly harm human health when particles are at ground...

Regional climate projections can provide information on likely future changes in climate, ecosystems, and water resources at useful scales.

In the Pacific Northwest, average temperatures are projected to increase by at least two and up to 15° F by end of the century, dependent on future greenhouse gas emissions levels. Winters are expected to become wetter and summers drier, snowpack will likely decrease substantially, and snowmelt runoff may occur earlier in the year. Wildfires are projected to become more frequent and more severe, and...

Climate scenarios provide a consistent set of possible future conditions to inform analyses of the risks posed by climate change.

The Fourth National Climate Assessment (NCA4) assesses risks to the United States posed by climate and global change. Scenarios that represent a range of plausible future changes in key risk drivers, such as greenhouse gas emissions levels, weather and climate extremes, sea level, population, and land use, are used to guide NCA4’s evaluation of specific climate-related risks in regions and sectors across the...

Researchers are improving understanding of how shifts in climate conditions affect agricultural production, as well as the value of providing advance climate information to producers.

Climate variability and change affect agricultural yields and livelihoods^[1]. Improving our understanding of how the interaction of climate variability and change affects agricultural production, particularly on regional scales that are more relevant to decision making, is an important research frontier. As part of the joint NSF-USDA...

Collaboration across the modeling community supports critical experiments and scientific advancement.

U.S. climate modeling centers play a central role in understanding and predicting global change on seasonal to centennial timescales. They are engaged in the Coupled Model Intercomparison Project (CMIP), which produces climate projections underpinning the assessments conducted by the Intergovernmental Panel on Climate Change and the U.S. National Climate Assessment. Models developed by these centers are designed for different purposes, from providing operational forecast...

The figure shows long-term averages of Arctic summer sea ice concentration simulated by an adaptation of CICE/Icepack

Interagency collaboration supports predictions of Arctic sea cover used by the U.S. Navy and other operational and research organizations.

Summer sea ice cover in the Arctic Ocean shrunk significantly since the early 1980s, with particularly rapid declines in recent years^[1]. Arctic sea ice plays a key role in regulating weather and climate in and beyond the region^[2], and projections of how sea ice cover will change in the coming years are critical for...

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Highlights

Advancing seasonal predictions of Arctic sea ice

Understanding carbon cycling in Arctic ecosystems

Collaborative modeling experiments to improve understanding of the future of the Earth system

Exploring human and natural influences on climate

Understanding the health benefits of reducing aerosol pollution

Modeling future climate, vegetation, and hydrology in the Pacific Northwest

Scenario products supporting the Fourth National Climate Assessment

Modeling the impacts of climate variability on agriculture

Enhancing coordination among U.S. modeling centers

Predicting Arctic sea ice change