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 2017 annual minimum ozone detection of 131 Dobson Units over Antarctica was observed on October 9, 2017, about a week later than usual, indicating that ozone levels may be starting to recover.

Interagency collaboration sustains long-term measurements that track the health of the ozone layer.

Ozone gas in the upper atmosphere protects the planet’s surface from harmful solar radiation. The Antarctic ozone hole was discovered in 1985, increasing concerns about human emissions of gases that destroy ozone and the negative consequences for life on Earth. Two years later, the international community signed the Montreal Protocol, an international treaty designed to protect the ozone layer through regulation of ozone-depleting compounds. Later...

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...

Longitudinal cross-section of 1998–2016 SHADOZ ozonesonde total column ozone (O3)

Balloon-borne instruments measure ozone levels high in the tropical atmosphere, providing new data to help refine projections of future climate change as well as educational opportunities for students in participating countries.

Ozone is a powerful greenhouse gas and an important contributor to global climate change. Its impact on the climate is strongest in a region of Earth’s upper atmosphere (upper troposphere and lower stratosphere) where it influences the amount of energy that escapes to space. Ozone distribution in this region is influenced by the upward...

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...

G-LiHT measurements for an area within Bonanza Creek Experimental Forest near Fairbanks, Alaska.

Scientists are using aerial and ground survey methods to measure change in Alaska’s interior forests and its impact on ecosystem services.

The boreal forests of interior Alaska are changing rapidly as the climate warms. Wildfires are more frequent and more severe, and declines in growth of spruce trees may be driving a shift towards ecosystems normally found in warmer climates. These changes can have significant impacts on the quality of wildlife habitat and ecosystem services that support the subsistence economies of many native Alaskan...

Using 29 years of data from Landsat satellites, researchers at NASA found extensive greening in the vegetation across Alaska and Canada.

Scientists are using satellites to collect detailed data on forest change in remote parts of Alaska and the Arctic.

Rapid warming in the Arctic and boreal regions of Alaska is affecting boreal forests and tundra ecosystems in a number of ways. Higher temperatures and changes in precipitation have led to a higher incidence of wildfire and increased tree mortality from drought, insects, and disease. Increases in the length of the growing season and the amount of energy produced by vegetation have also been observed. While tracking how climate...

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...

AmeriFlux FLUXNET2015 data collection sites overlaid on a map of global land cover types.

A global data collection network has built a strong foundation for carbon cycle understanding.

The AmeriFlux Network, which is supported by the Department of Energy, connects scientists from across the Western Hemisphere studying the exchange of carbon, water, and energy between ecosystems and the atmosphere. Since its launch in 1996, AmeriFlux has built a data record from 213 sites worldwide, called...

Analysis of the costs and benefits of switching to paddy rice production suggests that farmers could increase profits while reducing greenhouse gas emissions.

Drainage of organic soils for agriculture has resulted in widespread soil subsidence (sinkage relative to surrounding areas) and increased greenhouse gas emissions. The Sacramento-San Joaquin Delta in California, once an expansive wetland, was drained and converted to agricultural production in the mid-1800s, and has since experienced subsidence rates that are among the highest in...

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Highlights

Monitoring recovery of the ozone layer

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

Exploring human and natural influences on climate

Measuring ozone in the tropics

Advancing seasonal predictions of Arctic sea ice

Monitoring change in Alaskan forests

Detecting the drivers of forest change in Alaska and the Arctic

Understanding carbon cycling in Arctic ecosystems

Supporting twenty years of carbon cycle understanding

Informing agricultural emissions management