According to only the Native American tree core record (C) taken from the building, did droughts occur for longer or shorter time periods as the years progressed?

  When we look at climate models, if you delete the current anthropogenic (human made) causes of climate change temperature decline. 

Greenhouse gases absorb:

The PDO negative phase…..

The loss of Arctic Sea Ice can result in a: 

You are researching ice cores.  The bottom of your core has been dated at 500 CE (common era).  The ice at this depth and age contains a higher ratio of O18 (Oxygen Isotope 18) than O16 (Oxygen Isotope 16).  What can you conclude about the temperatures and the amount of ice on Earth at this time?

Oceanographers or geographers that study climate change can use foraminifera to see what type of oxygen was around at a certain year before present because their shells are composed of calcium carbonate.  Calcium carbonate contains __________ that are used to calculate past climates.

The regional changes in weather and climate patterns that are occurring attribute to anthropogenic greenhouse emissions is called

  The Paris Agreement lays out global commitments on climate change to reduce CO2 starting in 2020 and was signed by 174 countries.  The expected primary result of the agreement is to limit global warming to less than ___

This dendrochronology record is from Arizona. The thick layers could be representative of __________ .