Scientists Discuss Climate Temperature Trends | WAMC

Scientists Discuss Climate Temperature Trends

Jan 15, 2020

Last year was the second-hottest year on record. That was the conclusion at the 100th American Meteorological Society Annual Meeting in Boston, where experts from NASA and NOAA discussed major climate trends detailed in an annual assessment of global temperatures.

The National Aeronautics and Space Administration – NASA – and the National Oceanic and Atmospheric Administration – NOAA – issue an annual report detailing global temperatures over the past year. The report compares data to records that have been collected since 1880.  The just-released “Assessing the Global Climate in 2019” from NOAA’s National Centers for Environmental Information found that last year was the second warmest since they have logged records.  Global Monitoring Chief Deke Arndt explained that data includes land and ocean temperatures.   “It was second warmest both over land areas, ocean areas, and the combined land and oceans. All of them second to 2016. We were again about a degree Celsius warmer than this 20th century base period, that's 1.71 degrees Fahrenheit. Portions of the western Indian Ocean, and large chunks of the southwest and northwest Pacific were record warm. The prairie provinces of Canada and the northern United States experienced a relatively cool year relative to the local long term. But averaged all together, again, the second warmest year on record.”

NASA uses a slightly different data set and compares separate analyses from the World Meteorological Organization, Copernicus- the climate change service of the European Commission, and the UK Met Office – Britain’s national meteorological agency.  NASA Goddard Institute for Space Studies director Gavin Schmidt says they all agree that global annual temperatures are increasing.  "The trends are very, very similar, though the individual rankings from one year to another may be a little bit different. So for instance the Hadley Center CRU (UK Met Office Hadley Centre Climatic Research Unit) data has 2019 as the third warmest. But the fact is that the planet is warming. And the main thing here is not really the ranking but is the consistency of the long term trends that we're seeing."

The annual 2019 Global Climate report finds that temperatures were 1.71 degrees Fahrenheit higher on average with “record annual high temperatures ….measured across parts of central Europe, Asia, Australia, southern Africa …North America and eastern South America.”  Record ocean surface temperatures were also observed.  Schmidt says data analysis clearly indicates that the warming is due to human activity.  “We can just think about the changes that would have happened without us. So the volcanoes, the solar cycle, the orbital forcing. And when we do that, and we estimate what the temperature pattern would be just because of those, we end up with a massive discrepancy. And that tells us that the natural forcings are not capable of explaining the trends that we've seen since the 19th century. But you put together all of the natural and the human caused part of it, what you end up with is a very clear match to the observations. We end up with an attribution of these trends to human activity pretty much at the hundred percent level.”