At the present time, climate change is taking the form of global warming. That is, the trend lines for the average global temperature are rising. With that rise come a host of associated consequences and symptoms like melting glaciers, receding snow lines, rising ocean levels, severe droughts, changing biogeographies and others.
There are currently several sophisticated climate models that are used to predict or anticipate how the temperature trend lines will move in the future. All present models indicate that the trend of global warming is going to continue. The continuation will persist for as far into the future as the models can accurately forecast. Computer models are extremely valuable tools for the information they can generate. However, they are hampered by what they cannot do and for the limitation on information that lies behind the analogs they generate.
The present models are based on everything climate scientists know. The solar output, the location of the Earth in its orbit, the dynamics of Earth’s solar reflection, global winds, global ocean currents, ocean oscillations and other factors, are all placed as data into computer databases and analogs. The computers run mathematically precise operations to generate outcomes.
The problem is that the models do not contain all the different variables that influence climate. The reason for this is that climate scientists do not know all the variables that influence climate. The information scientists have is incredible and the forecasts they have made have proven to be reasonably reliable. However, consider one example of an interesting variable that has been observed, which will have to be studied and added to the models.
The well known El Nino event that forecasters monitor is an ocean oscillation or swelling that arises in the far western Pacific. It reverses the normal surface current, which rises off South America and flows westward to Indonesia, making a strong eastward current that rises in Indonesia and flows westward toward South America.
What scientists have observed is that a new ocean oscillation has emerged. It’s being dubbed in the media “a new kind of El Nino.” Rather than being in the eastern Pacific, it arises far to the west in the central Pacific. It is expected to cause an increase in the average number of tropical storms generated over oceans and in the number of storms moving onto shore.
The significance of this for climate modelers is that it demonstrates how, as global temperatures rise, critical points are passed that bring into play unforeseen events and consequences and new questions. Are higher temperatures generating more ocean oscillation activities? How will these critical influence climates around the world? How should computer models be modified?
Climatologists are well aware that historically, during interglacial periods, temperature trends rise to a critical point and then reverse into a temperature decline, ultimately leading to a glacial age. In the glacial age, temperatures bottom out and then reverse, warming again until the Earth enters a new interglacial period, completing a full climatic glacial cycle. Although there is much speculation as to the cause of this reversal, current research has not found the actual cause(s) that trigger these reversals.
The present body of observations suggests that continued forcing of greenhouse gases into the atmosphere will accelerate the glacial cycles, pushing temperatures higher more rapidly than does the natural process, bringing about a reversal much sooner than nature would without the forcing. What other critical trigger points will be passed along the way is unknown.
For more information see “2009-10 El Nino near certain: new kind of hurricane threat discovered.”