Ancient trees are revealing new findings about human-caused drought
NASA has only been studying soil moisture from space since 1980
Which meant that scientists needed an older,
but reliable record to understand our past climate
Researchers can use tree data to map droughts as far back as 1400
The result?
We now know that greenhouse gases caused by humans
have been affecting global drought since the early 20th century
How do we know?
Tree ring data is amazingly accurate
The rings are thinner in years when it’s dry and may not grow at all in stressful conditions like drought
Look Closer: Signal for human-caused climate change
This is the first study to provide historical evidence connecting human-generated emissions
and drought at near-global scales between 1900 and 2005
Together, modern soil moisture measurements and tree ring-based records
of the past create a more complete data set
Verifying the accuracy of climate models that predict more frequent drought in the near future