![NOAA-sponsored research shows that mobile sensors are a low-cost, effective way for U.S. cities to map their carbon dioxide emissions](/sites/default/files/LightRailCO2_footprints_rotator_480x320.png)
A single sensor deployed on a light-rail public train could provide as much information about the city's carbon dioxide emissions as 30 stationary monitoring stations, at a fraction of the cost.
![Doesn't carbon dioxide in the atmosphere come from natural sources?](/sites/default/files/douglas_fire_usda_480.jpg)
Yes, there are, but the only new process on Earth that has been identified that can account for the significant tipping of Earth's carbon balance is human activity, including deforestation, biomass burning, cement production, and—especially—fossil-fuel emissions.
![First saildrone circumnavigates Antarctica, seeking carbon dioxide](/sites/default/files/saildrones_redeployed_square_wings_480.jpg)
Despite a run-in with an iceberg and the world’s worst sailing conditions, Saildrone 1020 successfully completed its 13,670-nautical-mile journey around Antarctica, and indicated that parts of the Southern Ocean emit carbon dioxide in winter.
![Cruises cut a slice through the Atlantic's carbon pie](/sites/default/files/N%26F_HumanCO2andAtlanticOceanRotator_480x320.jpg)
About a third of the carbon dioxide released by fossil fuel burning winds up in the global ocean. Repeat cruises help scientists understand what happens to that carbon below the water surface.
![Desert-rainforest transition zones are hotspots for carbon storage, but not during El Niño](/sites/default/files/Semi-arid_Ecosystems_and_CO2_sink_rotator_480.png)
Plants on land have helped slow global warming by capturing nearly a quarter of the carbon dioxide that human activities release in an average year. But where is it all going?
![2014 State of the Climate: Fires](/sites/default/files/BiomassBurning_2014_480.jpg)
Globally, carbon emissions from fires were near the long-term average in 2014, but North America's emissions were 70% higher than average.
![Climate change likely to worsen U.S. and global dead zones](/sites/default/files/Changes_in_DeadZones_rotator_480.png)
Already a threat to fish, mussels, and other marine creatures, low-oxygen “dead zones” are expected to increase in both size and number as greenhouse gas concentrations and global temperatures continue to rise.
![In response to warming, Eastern forests inhaling more carbon dioxide than they're exhaling](/sites/default/files/ShiftsinForest_Phenology480x320.jpg)
In response to recent decades' warming, forests in the eastern United States have been "inhaling" more carbon dioxide through photosynthesis than they've “exhaled” through respiration.
Ariane Arias-Ortiz discusses her journey to her current career.