The year 2016 is on track to be the warmest year globally on record, according to NASA and other agencies’ measurements. There can be little doubt of this. Next year, relative to this year, may bring a slower rate of warming. And that will lead to confusion and misrepresentation, but not by climate scientists, most meteorologists and physicists. It will be more a matter of misinformation coming from those with an agenda who will be busy cherry-picking the data to support their arguments that global warming isn’t occurring, or that it isn’t a big deal because we have little to do with it.
This past autumn and winter brought the world the strongest El Nino since 1997-98, and possibly the strongest on record. The building and movement of vast areas of abnormally warm tropical waters in the largest ocean, the Pacific, sent vast amounts of heat into the atmosphere. This surge of extra atmospheric and ocean warming occurred on a background of already ongoing global warming (on average), helping to produce a big spike in the global average significantly beyond the warming in place.
El Nino has been gone now for several months, with somewhat cooler than average surface/near surface water temperatures having returned to the central and eastern tropical Pacific. There may be some lingering feedback mechanisms still occurring in some small way.
However, we have now experienced our 14th consecutive record warm month globally, far beyond the range of El Nino’s impact before and after its occurrence. Even so, without this extra El Nino-related spiking, next year’s rate of warming will probably not match this year’s rate. Warming denialists will probably point to the spike as strong evidence that natural, not manmade influences, are the main forcing agents for warming. That is what occurred after the record-breaking spike of 1997-98. The rate of warming for a number of years in general could not match that enormous El Nino-related spike of warming. That began the myth that global warming had stopped or, in some extreme views, been reversed.
In fact, the rate of atmospheric warming did slow down for a number of years. Warming is never “linear,” or constant in rate. There are spikes and valleys over a decade, but the mean or median warming never stopped rising. Its rate changed; not its reality. And, during this perceived lull, the oceans continued to act as a heat and carbon sink. That is, ocean waters absorb a significant amount of atmospheric heat and carbon. The added CO2 continues to produce acidification in the oceans, endangering coral and other life forms. The median warming has continued to shrink average ice cover including arctic sea ice and the tremendous Greenland ice cap, along with most glaciers. Sea levels have continued to rise at uneven rates globally due to melting freshwater ice runoff and due to expansion from warming sea temperatures (water expands in volume when it is heated).
So, my forecast is that denialists will seize on the probable reduced rate of warming next year and dispense either disinformation (from politically motivated sources) or misinformation (from a genuine lack of understanding).
In the meantime, there are now more than 24 climate models which predict broad climate trends (not short term weather—that background “noise” is eliminated). When any of them run on the basis of the approximate 300 parts per million of C02 around 1900 in the atmosphere rather than the current and increasing 400+ parts per millions, they all show the earth would have been in a weak cooling cycle since, even if the models ramp up other natural warming forces, such as solar input.
Climate scientists, atmospheric physicists, chemists and oceanographers can find no other explanation for the warming which has been occurring other than human activity. There are uncertainties on the rate of warming, how much and how fast additional warming will occur, and what some impacts will be. But there is no peer-reviewed evidence that human activity is not the main source of this warming.