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. Highlights describe the state of science at the time of publication of each yearly report, and may not reflect more recent advances in understanding. The date of publication of the source report is noted on each highlight page.

The U.S. research centers that develop climate and Earth system models and the U.S. scientific community are key participants in long-running collaborative efforts to improve knowledge on climate change. A number of major interagency activities supporting improvements in climate modeling took place in 2019.

Most prominently, the World Climate Research Programme Coupled Model Intercomparison Project (CMIP) is currently in its sixth phase (CMIP6). The earlier phases of CMIP experiments have provided the research community...

Methane emitted from thawing permafrost below an Arctic thermokarst lake is trapped in bubbles of many different sizes and shapes as the ice grows during the winter.

Long-frozen northern soils known as permafrost contain one of the world’s largest stores of organic carbon. This reservoir is stable while soils are frozen, but as permafrost thaws, decomposition of biomass by microbes produces the heat-trapping gases carbon dioxide and methane, returning soil carbon to the atmosphere where it contributes to climate change. Permafrost carbon stores are expected to be increasingly vulnerable to decomposition as the climate continues to change, leading to a feedback cycle of further warming and permafrost thaw.^[1]...

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...

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...

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...

Modeling efforts provide new data on the effects of climate change in Antarctica.

Between 1998 and 2016, warming in Antarctica has been rapid and significant. Recent observations also reveal increases in snowfall in western Queen Maud Land, East Antarctica that are unprecedented over the past two millennia. To investigate these changes, a team of NSF-sponsored researchers and NASA scientists merged observation-based NSF-funded research with global modeling efforts that benefited from NASA satellite and airborne-based data^[1]...

Over the Great Plains region of the United States, summertime thunderstorms often occur after sunset. Much of this nighttime rainfall is caused by large, organized storm systems and plays a critical role in the hydrology and agriculture of the region, especially over the more arid western Great Plains. During the summer months, these nighttime storm systems provide 30-70% of the region’s precipitation and can also cause severe weather, including flash floods, intense damaging winds, and large hail. Current weather and climate models have difficulty predicting the onset, location, frequency...

As climate change increasingly impacts society and ecosystems, demand for reliable information about climate conditions now and in the future is growing. Climate research is conducted by two distinct communities, one working on climate forecasts for the near-term future and the other on climate-change projections over decades to centuries. Despite these different foci, the boundaries between these two communities increasingly overlap, and they share many common methods and challenges. Enhanced collaboration across modeling centers and communities can help create more valuable climate-...

The U.S. Climate Modeling Summit brought together representatives from the Nation’s major experimental and operational climate modeling programs. Above, Summit participants gather at the NOAA Center for Weather and Climate Prediction. (Source: NOAA)

Modeling Earth’s climate furthers priorities of national interest, from experimental research to understand the Earth system to operational forecasts and projections that inform decisions. Coordination among the Nation’s premier modeling centers—particularly between experimental and operational programs (see also Highlight 31)—has the potential to advance forecasting capabilities, yield more robust predictions, and bridge models of near-term weather and longer-term climate that currently are separated by high-uncertainty gaps in coverage.

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Highlights

Modeling efforts drive advances in projections of future climate change

Scientists investigate the effects of carbon emissions from thawing permafrost soils

Exploring human and natural influences on climate

Understanding carbon cycling in Arctic ecosystems

Modeling the impacts of climate variability on agriculture

Enhancing coordination among U.S. modeling centers

Modeling ice sheet change in Antarctica

Studying Thunderstorms by Night

Improving Climate Predictability

Building Synergy in the U.S. Modeling Community