With cause of large majority of deviation of current temps from trend being unknown, this makes it hard to speculate too much whether this is likely to return to trend rapidly or not and whether there is much any risk of 2016 being cooler than 2015.
Without knowing cause of majority of deviation from trend or any detail of how likely a rapid return to trend and then go in opposite direction is, I think it is hard to completely rule it out.
I would suspect it is very unlikely there could be such a rapid reversal soon enough and therefore there is very little risk of 2016 being cooler than 2015. Perhaps surprising that predictions are being made without referring to this issue?
Given the large number is different parameters in Earth Systems Models, all with different confidence ranges, it is not surprising that a modeler like Gavin Schmidt might say "Wow!" when he saw the observed 2016 GMST; as there is a wide range of projected GMST values in the CMIP5 models. However, as discussed in the three linked references (see images) Earth Energy Imbalance, EEI (or Global Energy Imbalance or Planetary Energy Imbalance), is a more fundamental measure of climate change than is GMST and it is much less subject to noise due to such factors as: the ENSO cycle, multi-decadal cycles like the PDO/IPO (which are both now positive), and cold spots in the North Atlantic, and Southern, Oceans due to rapid glacial meltwater pool at the surface while deeper, more saline, seawater remains relatively warm.
K. von Schuckmann, M. D. Palmer, K. E. Trenberth, A. Cazenave, D. Chambers, N. Champollion, J. Hansen, S. A. Josey, N. Loeb, P.-P. Mathieu, B. Meyssignac & M. Wild (2016), "An imperative to monitor Earth's energy imbalance", Nature Climate Change Volume: 6, Pages: 138–144, doi:10.1038/nclimate2876
http://www.nature.com/nclimate/journal/v6/n2/full/nclimate2876.html&
https://www.researchgate.net/publication/292188056_An_imperative_to_monitor_Earth%27s_energy_imbalanceMatthew D. Palmer, Met Office Hadley Centre, Exeter, United Kingdom (2016), "Earth’s energy imbalance and the global warming ‘hiatus’: insights from climate models and ocean reanalyses"
https://agu.confex.com/agu/os16/preliminaryview.cgi/Paper88665.htmlMatt Palmer and Doug McNeall (UK Met Office) (2016), "Earth's energy imbalance"
http://www.climate-lab-book.ac.uk/2016/earths-energy-imbalance/Extract: " All the energy that enters or leaves the Earth system does so via radiation at the top of the atmosphere. For a stable climate, the sunlight absorbed by the planet must be balanced by thermal infra-red radiation emitted to space. Increased atmospheric greenhouse gas concentrations give rise to an imbalance in Earth’s energy budget by initially reducing the amount of emitted thermal infra-red radiation. The result of this imbalance is an accumulation of excess energy in the Earth system over time. The size of the imbalance, or equivalently, the rate of energy accumulation in the Earth system, is the most fundamental metric determining the rate of climate change.
The vast majority (>90%) of the excess energy is absorbed by the ocean, with much smaller amounts going into heating of the land, atmosphere and ice cover (Figure 1). Therefore, if we want to track the increase in Earth system energy content over time it is essential to have comprehensive measurements of temperature, and the associated heat content, throughout our vast oceans.
As a result of the energy imbalance, the Earth system adjusts in a number of ways that have a direct impact on both the marine and terrestrial environment. The various elements of global warming that we are familiar with – including global surface temperature rise, reductions in snow and ice cover, and sea level rise – can be thought of as symptoms of EEI (Figure 2). In our thinking and communication around climate change, it is important not to confuse any of these symptoms with the underlying cause.
A large part of the controversy around the recent slowdown in surface temperature rise, or ‘hiatus’, stems from the fact that many commentators view global surface temperature rise as the primary indicator of global climate change. If surface warming has paused, climate change has paused, right? Wrong. Both observational studies and computer simulations show that there is only a weak relationship between Earth’s energy imbalance and surface temperature change over a decade or so (Figure 3a). This is because natural climate fluctuations can re-arrange ocean heat content, to either offset or add to the long-term rate of global surface temperature rise over a decade or so.
Since the ocean becomes the dominant term in Earth’s energy budget on timescales longer than about 1 year changes in ocean heat content provide a much more reliable indicator of EEI (and therefore climate change) than surface temperature on decadal timescales (Figure 3). Indeed, time series of upper ocean heat content and satellite measurements agree on a fairly steady rate of heat uptake over the past 20 years or so, suggesting that EEI has also been relatively constant during this time (Figure 4). When viewed in terms of EEI, there is little or no evidence for a recent ‘hiatus’ in the rate of global climate change."
Thus is it plausible that: (a) during the recent faux hiatus heat content accumulated in all the oceans of the world, and that this accumulated heat is now contributing to a multi-decadal long upswing in GMST values; (b) during the rapid economic development of China the associated increase of aerosols were more effective at masking global warming than previously expected and that now with the worldwide focus on closing coal-fired power plants that several decades worth of global warming are now being rapidly unmasked; and (c) since 2008, atmospheric methane concentrations are up by over 5% (compared to 2000 to 2007) and with a GWP10 of 130, this could be contributing to the current spike in GMST. Also, considering the risk of a record low ASIE in 2016 and the associated increase in Arctic Amplification; it might be more advisable to err on the side of precaution and look at the upper bound of Gavin Schmidt's confidence range for projected 2016 GMST anom, and consider possible values closer to 1.5C than to 1.1C.