A new paper by Dr. Nicola Scafetta of Duke University examines the relationship of natural, solar-driven ocean oscillations such as the Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and the North Atlantic Oscillation (NAO) to the changes in rate of sea level rise. He finds no correlation with atmospheric carbon dioxide or temperature.

Before I get into the Scafetta paper, here is some background.

Measuring sea level is more complicated than pounding a stake into a beach. Ideally, global sea level would be a rotating oblate ellipsoid of polar radius of 6365.752 km and equatorial radius of 6378.137 km in absence of any other forces. Gravity distorts this ideal shape to make it lumpy.

There are daily and seasonal variations, and storm surges in addition to the oscillations mentioned above. There are tectonic events: is the ocean rising or is the land sinking? Also, extraction of groundwater near coasts may cause the land to sink and present an apparent rise in sea level. All these confounding factors can produce a local rate of sea level change very different from global rate of change.

Since the end of the last glacial epoch, sea level has risen 120 meters (393 feet), about one meter per century. Sea level is still rising at the rate of 1- to 3mm per year, according to NOAA, about the thickness of one or two pennies.

As you can see from the figure, the rate of sea level rise has changed on broad time scales. Scafetta has found patterns of acceleration and deceleration of rise at much smaller time scales.

Scafetta studied six long-term tidal gauge records sited to represent all of the world’s oceans. He found the rate of sea level rise “…to be characterized by significant oscillations at the decadal and multidecadal scales up to about 110-year intervals. Within these scales both positive and negative accelerations are found if a record is sufficiently long. This result suggests that acceleration patterns in tide gauge records are mostly driven by the natural oscillations of the climate system. The volatility of the acceleration increases drastically at smaller scales such as at the bi-decadal ones.”

“Tide gauge accelerations oscillate significantly from positive to negative values mostly following the PDO, AMO and NAO oscillations. In particular, the influence of a large quasi 60–70 year natural oscillation is clearly demonstrated in these records.”

A conclusion from this paper has implications for climate model predictions: “at scales shorter than 100-years, the measured tide gauge accelerations are strongly driven by the natural oscillations of the climate system (e.g. PDO, AMO and NAO). At the smaller scales (e.g. at the decadal and bi-decadal scale) they are characterized by a large volatility due to significant decadal and bi-decadal climatic oscillations. Therefore, accelerations, as well as linear rates evaluated using a few decades of data (e.g. during the last 20-60 years) cannot be used for constructing reliable long-range projections of sea-level for the twenty first century.”

The cyclical nature of the rate of sea level rise, and its quite variable accelerations and decelerations at different time scales may explain why different researchers get different rate values. So, scary stories saying we are doomed because of acceleration in the rate of sea level rise, such as the ‘science fiction” stories linked below, should be taken with a grain of salt.

Reference: Scafetta, N., 2013, Multi-scale dynamical analysis (MSDA) of sea level records versus PDO, AMO, and NAO indexes, Climate Dynamics, DOI 10.1007/s00382-013-1771-3.

See the full paper here.

See also:

Science Fiction from the University of Arizona?

More science fiction from the University of Arizona

University of Arizona dances with sea level

Sea Level Rising?

Sea Level Rise in the South Pacific: None

Sea Level Rise Declining says EU

Obama parts the waters, sea level drops

Size matters in sea level studies

Sea level rising fast along American East Coast – or not

Dr. Norman Page says that “The earth is entering a cooling phase which is likely to last about 30 years and possibly longer.” See his detailed analysis here.

Page’s prediction is based on observation of the geologic record. He notes that there has been no net warming since 1997 even thought carbon dioxide content of the atmosphere has risen 8.5%. Page says that atmospheric temperature is driven by sea surface temperature (SST) which is, itself, solar driven. The oceanic oscillations control the general climate. There is good correlation between solar cycles and SST, but note that because of the enthalpy and thermal inertia of the oceans, there is a 10 – 12 year lag between solar cycle troughs and global SSTs. This lag time definitely establishes cause and effect similar to the lag in carbon dioxide changes following temperature changes in the major glacial cycles as shown in ice cores The graph below shows the variations in the Pacific Decadal Oscillation (PDO), the major oceanic oscillation (the red line is actual measurement, the blue line is predictive modeling.) (Graph source here.)

Page says than in the figure “an approximate 60 year cycle is obvious by inspection and this coincides well with the 30 year +/- positive (warm) and 30year +/- negative (cold) phases of the Pacific Decadal Oscillation.” The graph “shows warming from about 1910 to 1940-45, cooling from then to about 1975, warming to about 2003-5 and cooling since then. Total warming during the 20th century was about 0.8 degrees C.” He also says that it is clear that we are entering the beginning of a 30-year cool phase of the PDO.

Page goes on to say:

“The major ice age climate cycles are controlled by the sun – earth orbital eccentricity, and the earth’s obliquity and precession. These cycles are approximately 100,000, 41,000 and 21,000 years in length respectively and are well documented in the ice core and geological record. It is useful to keep in mind that the warmest temperatures in the current interglacial occurred about 7500+/- years ago and the general trend is now a cooling towards the next ice age.”

“These long term cycles are modulated by quasi cyclic trends in solar activity which may be decadal, centennial, or millennial in length. Of particular interest in deciding where we are with regard to the solar cycles is the approximately 1000 +/- year cycle which produced successively the Roman Warm Period, the Dark Ages, the Medieval Warm Period, the Little Ice Age and the recent 20th century warming.”

These cycles are shown in the 2,000-year temperature reconstruction below (the white line is the smoothed curve):

Page says that “A reasonable case can be made that the warming peaks of a 60 year PDO cycle and the 1000 year solar cycle coincided at 2000 +/- and we are likely on the cooling slope of both.”

For a broader view, the graph below shows a temperature reconstruction for the past 11,000 years:

In his conclusion, Page says “Often the signal for a climate direction change is a see-saw effect between Arctic and Antarctic sea ice. The Arctic is still reflecting the peak in the warming trend with low summer ice values. The first indication of a cooling event is however the increase in Antarctic sea ice which has already occurred.” (See my post: The Arctic-Antarctic seesaw)

Page is not alone is his prediction. Two years ago I reported that NASA was also predicting a cooling period based on the same natural parameters. (See NASA Says Earth Is Entering A Cooling Period).

If this predicted cooling trend comes to pass, it will show, once again, that the forces of natural variation easily overcome the weak warming effect of carbon dioxide. And, by the way, if indeed the predicted cooling trend proceeds, atmospheric carbon dioxide will decrease because a cooler ocean can absorb more carbon dioxide.

This phase shift has some policy implications. It shows that curbing carbon dioxide emissions from burning fossil fuels is unnecessary and perhaps contraindicated. If you believe that such emissions do have a significant effect on global temperature, we should continue and perhaps even increase emissions to forestall or lessen the effect of the cooling trend lest we find ourselves in another “little ice age.”

In a previous post I reported research from Norwegian marine sediment cores and temperature proxies that showed that the current warming period was not only not unusual but also cooler than the Medieval and Roman warming periods.

Reference:

Sejrup, H.P., Haflidason, H. and Andrews, J.T. 2011. A Holocene North Atlantic SST record and regional climate variability. Quaternary Science Reviews 30: 3181-3195.   Abstract here.  Their graph:

A commenter on the previous post dismissed the research saying it was for only one region and did not necessarily represent global temperature history.

Well, here is more research showing that the results found in Norway were similar to results found globally:

Reference:

Bertler, N.A.N., Mayewski, P.A. and Carter, L. 2011. Cold conditions in Antarctica during the Little Ice Age — Implications for abrupt climate change mechanisms. Earth and Planetary Science Letters 308: 41-51.

From ice cores, the researchers were able to identify the temperature differences of the Medieval Warm Period (AD 1140 to 1287), the Little Ice Age (AD 1288 to 1807), and the Modern Era (AD 1808 to 2000). They found “the McMurdo Dry Valleys were 0.35°C warmer during the MWP than now, accompanied by warmer conditions in the Ross Sea.”

Reference:

Liu Y, Cai Q F, Song H M, et al., 2011, Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau. Chinese Sci Bull, 56: 2986 2994, doi: 10.1007/s11434-011-4713-7.

These researchers show that the Medieval Warm period was at least as warm as the current period.  See my post on the paper here.

Reference:

Hu, F.S., Ito, E., Brown, T.A., Curry, B.B. and Engstrom, D.R.  2001.  Pronounced climatic variations in Alaska during the last two millennia.  Proceedings of the National Academy of Sciences, USA 98: 10,552-10,556.

Using sediment cores from Farewell Lake in the northwestern foothills of the Alaska Range, the researchers found that surface water temperatures during the Roman Warm Period and the Medieval Warm Period were the same as those now.

Reference:

Hong, B., Liu, C.-Q., Lin, Q.-H., Yasuyuki, S., Leng, X.-T., Wang, Y., Zhu, Y.-X. and Hong, Y.-T. 2009. Temperature evolution from the ä18O record of Hani peat, Northeast China, in the last 14000 years. Science in China Series D: Earth Sciences 52: 952-964.

Using cores extracted from peat deposits in Northeast China, researchers used oxygen-18 analysis and concluded that the Medieval Warm Period in China peaked about 900 AD and was 1 C warmer than the current warm period.  They also found that “sudden cooling events, such as the Older Dryas, Inter-Allerod, Younger Dryas, and nine ice-rafted debris events of the North Atlantic are almost entirely reiterated in the temperature signals of Hani peat cellulose ä18O.”

Reference:

Millar, C.I., King, J.C., Westfall, R.D., Alden, H.A. and Delany, D.L. 2006. Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA. Quaternary Research 66: 273-287.

Using temperature reconstruction from tree rings, the researchers concluded that the Medieval Warm Period in Nevada was “significantly warmer” (+3.2°C) than present.

Reference:

Kaniewski, D., Van Campo, E., Paulissen, E., Weiss, H., Bakker, J., Rossignol, I. and Van Lerberghe, K. 2011. The medieval climate anomaly and the little Ice Age in coastal Syria inferred from pollen-derived palaeoclimatic patterns. Global and Planetary Change 78: 178-187.

Analyzing pollen contained in sediment cores from alluvial fans, the researchers found evidence that suggests “three peaks centered on ca. 1115, 1130 and 1170 cal yr AD suggest similar or warmer temperatures compared to AD 2000.”

Reference:

Neukom, R., Luterbacher, J., Villalba, R., Kuttel, M., Frank, D., Jones, P.D., Grosjean, M., Wanner, H., Aravena, J.-C., Black, D.E., Christie, D.A., D’Arrigo, R., Lara, A., Morales, M., Soliz-Gamboa, C., Srur, A., Urritia, R. and von Gunten, L. 2011. Multiproxy summer and winter surface air temperature field reconstructions for southern South America covering the past centuries. Climate Dynamics 37: 35-51.

Using multiple temperature proxies, the researchers concluded the warmest decade of this Medieval Warm Period in Southern South America was AD 1079-1088, and that was about 0.17°C warmer than the peak warmth of the current warm period.

Reference:

Holmgren, K., Tyson, P.D., Moberg, A. and Svanered, O.  2001.  A preliminary 3000-year regional temperature reconstruction for South Africa.  South African Journal of Science 97: 49-51.

These researchers deduced temperature variations from stalagmites in caves.  They estimate that the Little Ice Age between AD 1500 and 1800, was about 1°C colder than they are presently.  During the Medieval Warm Period at around AD 900 temperatures reached 2.5°C higher than at present.  Another exceptionally warm period was noted in the late fifteenth century, when temperatures rose more than 3°C above the current level.

The foregoing gives just a few examples showing that climate is cyclical and current temperatures are not unusual.  There is still no credible evidence that I am aware of that supports the contention that our carbon dioxide emissions are the major cause of recent warming.  For another overview see here.

In the current warm period, temperatures are increasingly artifacts of poor station siting that creates a warming bias (see Surfacestations.org) In a study of U.S. stations it was found that “9 of every 10 stations are likely reporting higher or rising temperatures because they are badly sited.”  Part of the problem is that many stations are in or near growing cities and suffer from the Urban Heat Island effect, i.e., during the day, the sun heats concrete and asphalt which then radiate heat at night making temperatures in the cities (and at the stations) warmer than rural areas.  And, there is also the problem of data manipulation by government agencies with an agenda.

For some additional perspective, the graph below shows global temperature as measured from satellites, beginning in 1979.  Although atmospheric carbon dioxide has been increasing, there does not seem to be a corresponding temperature response.  In the graph, temperatures before the strong El Nino event in 1998 show no trend.  Temperatures after 1998 also show no trend.  The difference is temperature levels before and after is attributed to shifts in global atmospheric cycles such as the Pacific Decadal Oscillation and El Nino.