There are millions of measurements over the last hundred and 40 odd years.
We put those together.
We're using data from literally tens of thousands
of different stations around the world.
We use the information that's there to create a global picture
of what's happening.
And that gives us a very accurate
estimate of how any year ranks or what the
what the anomaly is for any one year compared to what happened
in the 19th century or what happened in the middle of the 20th century.
So we have our statistical reconstruction of Earth's recent climate.
But in research science, we like to check our work.
There are a couple of ways we can do this.
First of all, teamwork. Our colleagues at NOAA, and at other agencies
and universities around the world, also create their own records, and
we can line them up side-by-side, and see just how closely they align.
Everyone's independent climate records show the same thing:
Earth is warming significantly and rapidly.
And here at NASA, we have an even cooler way to check our work:
space!
Right now, we have more than
two dozen satellites dedicated just to studying our planet.
Satellites can take measurements of the entire planet,
and line them up with our estimate of global temperature change.
And sure enough,
they also match!
Our measurements from space match up well with what our analysis tell us:
Earth's climate is warming.