Another Hot Year!

This visualization illustrates Earth’s long-term warming trend, showing temperature changes from 1880 to 2015 as a rolling five-year average. Orange colors represent temperatures that are warmer than the 1951-80 baseline average, and blues represent temperatures cooler than the baseline. Credits: GSFC Scientific Visualization Studio

It turns out 2015 was the warmest year yet according to NASA and NOAA! It edged out 2014 (the last record holder) by 0.23° Fahrenheit (0.13° Celsius). This continues a warming trend over the last 35 years but with 15 of the warmest years happening since 2001. NASA used surface temperature measurements from 6,300 weather stations located across the globe to create a global average surface temperature.

Since consistent records started being kept in 1880, the planet's average surface temperature has risen about 1.8° Fahrenheit (1.0° Celsius). With temperatures rising due to carbon and other gas emissions it reinforces the need for change. With the recent Paris Climate Agreement hopefully the world can work work together to accomplish its aims of keeping global warming below 3.6° Fahrenheit (2.0° Celsius).


Source: NASA

Clouds are Accelerating Greenland's Melting

CALIPSO Satellite Path

CALIPSO Backscatter Data - Click for bigger image
The red line in the image is ~ ground level and corresponds with the purple line in the top image.

Greenland's ice sheet has been melting at alarming rates over the last few years and scientists are trying to piece together the story. One part that is becoming clear is the effects of clouds on the ice sheet. Recently published research in Nature Communications by an international team has shown that surface temperatures were three degrees Fahrenheit higher due to increased cloud cover over the Greenland Ice Sheet. Clouds act as blanket and hold heat longer in the atmosphere. You can see this effect at night when skies are overcast or clear. Overcast nights are warmer due to heat being trapped in by the clouds whereas clear nights are colder because heat escapes more easily. The effect in Greenland may be compounded because as more melting occurs, more moisture enters the atmosphere, and more clouds form.

This research was accomplished using ground measurements and NASA satellite data from CALIPSO and CloudSat. The images above are from CALIPSO which uses LiDAR, infrared, and visible imagers to measure cloud structure. CloudSat uses a radar system to profile cloud structure. For more information click on the source link below.

Source: Nature Communications
Images: CALIPSO