NASA is uniquely positioned to study our home planet, and Earth observation has been at the core of the agency's work since our founding. In addition to a fleet of amazing satellites that we and our international partners use to study our planet in a range of wavelengths, and across the spectrum of planetary features from oceans to atmosphere and ground cover, the International Space Station is also rapidly becoming a significant platform to study Earth.

Our work has global implications. This week, a small delegation of NASA leaders have been participating with a larger U.S. delegation at the 21st session of the U.N. Framework Convention on Climate Change (UNFCCC) Conference of Parties, also known as COP-21. COP-21 will bring nearly 200 nations together to reach an agreement on limiting climate change.

Global climate change, driven by rising levels of carbon dioxide and other greenhouse gases in the atmosphere, represents a fundamental challenge to the U.S. and the world. It is the challenge of our generation.

While NASA has no formal role in the COP-21 climate policy talks, the agency is hard at work providing the nation and the world the best information possible about how Earth is changing. Regardless of what world leaders decide in Paris, our job is to build an understanding of the whole planet now and what it will look like in the future.

NASA's comprehensive study of Earth has provided much of the underlying understanding of current trends in the planet's climate - including definitive measurements of rising sea levels, glacier retreat, ice sheet changes and the decline in the volume of the Arctic sea ice cap. Our satellites have provided global, long-term views of plant life on land and in the ocean.

And our supercomputing power is allowing us to better understand how all the parts of the Earth system work together and help us to predict how this could change. We will continue to monitor climate trends and investigate other ways in which the planet is ultimately responding to increasing greenhouse gas levels.

We have discovered more than a thousand planets outside of our solar system, but none yet match Earth's complexity. That's one reason we have more satellites orbiting Earth than any other planet. We made a significant expansion of the Earth-observing fleet in 2014 and 2015, launching missions that are making unprecedented measurements of rainfall and snow (Global Precipitation Measurement), carbon dioxide in the atmosphere (Orbiting Carbon Observatory-2), and soil moisture (Soil Moisture Active Passive).

Soon, with the help of NOAA, the French Space Agency CNES, the European Organisation for the Exploitation of Meteorological Satellites -EUMETSAT and SpaceX, we will launch the Jason-3 mission to continue building on the vital, two-decade record of how much and where global sea level is changing.

The view from space is incredible - seeing our planet from orbit is one of the highlights of my life - but sometimes we need to get in a little closer. So in the 2015 and throughout 2016, NASA is sending scientists on expeditions to all corners of the planet - by plane, by ship and even by foot - to get an on-the-ground look to help answer some important science questions.

How are warming ocean waters melting Greenland glaciers and adding to sea level rise? How are the world's coral reefs responding to changes in the ocean? What will rapidly warming temperatures in the Arctic mean for the greenhouse gases stored in forests and permafrost? Our scientists are putting together multi-year campaigns that will complement our space-based perspective. Consider it planetary exploration right here at home.

Global meetings like COP-21 are important for discussion and policymaking, and NASA will continue the day to day work of monitoring our Earth observation satellites and making their wealth of data available to people across the globe. There's no more important planet for us to understand.