OUTLOOK ON CLIMATE CHANGE – OBSERVER TIMES

In 2017, the Earth’s climate set alarming records for surface and ocean temperature as well as sea ice extent. Recent analyses by the National Aeronautics and Space Administration (NASA) and the National Oceanic Atmospheric Administration (NOAA) showed that 2017 ranked as either the second or third warmest year for global surface temperature on record since 1880, depending on the analysis method used. In the 136 year record of average near surface temperatures, 16 of the 18 warmest years have occurred since 2001. The average global surface temperature has now risen about 1.1ºC above pre-industrial levels averaged over the period 1850 -1900.

2017 was also the warmest year on record for ocean heat content. Heat content of the ocean is a more reliable indicator of climate change because oceans take up more than 90 percent of heat trapped by increasing greenhouse gas (GHG) concentrations, and ocean heat content increases more smoothly than surface temperatures. In addition to both of these records, 2017 also saw record-low sea ice in both the Arctic and Antarctic. As since continuing a long-term downward trend in global sea ice extent since the late 1970s. These trends are just some of the sobering signs of accelerating climate change.

The fuel for global warming is GHG concentrations that reached record levels by the end of 2017. The global annual average atmospheric concentration of carbon dioxide (CO2) was measured 2017 was also the warmest year on record for ocean heat content. Heat content of the ocean is a more reliable indicator of climate change because oceans take up more than 90 as more than 405 parts per million (ppm) in 2017. The record surpassed 400 ppm in 2016 for the first time in modern atmospheric measurements and in ice core records of the past 800,000 years. While these latest data are still preliminary, they confirm that cumulative GHG concentrations are increasing and are projected to reach a level roughly two to three times the highest level occurring over the last 800,000 years unless decisive and rapid measures are undertaken to sharply reduce emissions.