Are Sea Levels Rising or Falling?

Recently, I wrote a guest post (see link) on Anthony Watts’ world-class blog, WattsUpWithThat.com, the topic of which was a recent round of lawsuits (proposed and actual) related to climate change. In my writing, I made the statement that many dire events are predicted by the warmists when (if) the Earth’s climate becomes hotter due to man-made global warming. I wrote: (bold emphasis added for this post, not included in the original on WUWT)

“A greatly hotter planet is predicted to have dire consequences. Among the predicted events are millions of climate refugees, massive reduction in coral reefs due to ocean acidification, inundated seashores from rising sea levels, with the sea level increase caused by hotter ocean water and melted polar ice caps, frequent and unusually strong hurricanes or tropical cyclones, weather too hot to grow crops, prolonged and devastating heat waves, and outbreaks of heat-related diseases and the attendant deaths.” I then wrote “ The fact that CO2 has risen over the past 50 years, yet none of the dire events have occurred surely will not be overlooked by the defense attorneys. The facts that CO2 continues to rise, and the global and regional temperatures are falling, and the ocean levels are falling, and the ocean temperatures are falling, also will surely be emphasized by the defense attorneys.”

A reader then took exception to one phrase, “. . . and the ocean levels are falling, . . .” He or she challenged me to support that statement with evidence. So, I did. I wrote:

“ . . . the sea level data from sealevel.Colorado.edu shows a mix of ocean level trends, with some point locations rising, but some falling since the satellite measurements began in 1992. For example, my previous investigations for the data along the California coast shows a decrease in sea levels, not an increase. However, even the global mean sea level trend has stabilized since 2006, and shows a slight downward trend in some of the individual ocean basins. For example, the trend for the Pacific Ocean shows +0.23 mm/year since the end of 2005. However, there is a significant spike in the data for the last half of 2009, which is highly questionable as to its accuracy. Without that data spike, the trend since 2005 shows a decrease of (minus) -0.18 mm/year. By “without that spike,” my meaning is to manually adjust the data downward by 10 mm, starting with the data point labeled 2009.5741 and ending with 2009.927. This hand-correction opens up a can of worms, as criticism can be leveled at why should the correction be made only for those data points, and why choose 10 mm as the adjustment? Why not make similar adjustments to low-lying data?

My response to those arguments is that the data appears to have outliers, far beyond the normal range of data oscillations. In my professional experience as an engineer, such outliers deserve special attention to determine several things. First, do they indicate a problem with the measuring instruments? Second, if there are no instrument problems, was there a data transmission or recording or transcription error? Third, if none of those problems exist, and given what we know to be true in physics and engineering, is it physically possible, or even probable, that such a change in the measured parameter could happen in such a short time? Fourth, when a trend over time is the critical question, what is the impact of having the outlier included, and then excluded in that trend calculation? This last question is especially critical when the outlier cannot be explained.

This is a long way of saying that I don’t for a minute believe there was an upward spike in the actual sea level in the last half of 2009, across the entire Pacific Ocean. We may never know, of course, as it is impossible to go back in time to take the measurements again. We cannot repeat the experiment, in other words. Therefore, everyone can make of this what they choose. Some, of course, will disagree with me and they have every right to do so. I can see an inflection point in the global mean sea level trend, somewhere around the middle of 2005, as many others have noted and written on. What was a clearly rising trend suddenly became a zero trend, or with a slight declining trend if the apparently spurious spike in 2009 is taken away.

Thus, my statement that the ocean levels are falling. And, this is occurring even with a continuing increase in CO2. As developing economies consume greater quantities of coal, the increase in CO2 should escalate. If the warmists were correct, ocean levels should be rising at a greater rate. Clearly, they are not. Such evidence would be great fun to present in a court of law.”

Here, I will present the graphical support for the statements and conclusions above. Figure 1 (below) shows the sea level anomalies for the Pacific Ocean Basin since 1992, from the above-mentioned source, sealevel.colorado.edu as of May 4, 2011. The straight-line trend shows an average increase of 2.59 mm/year, or 259 mm per century. For Americans, that works out to barely more than 10 inches in a century; one inch per decade. (254 mm would be 10 inches, so this is only 5 mm more than 10 inches).

Figure 1

Pacific Ocean Basin Mean Sea Level Anomalies and Trend

(click on chart for larger version)

However, Figure 1 has a most interesting aspect. There is a definite break in the upward trend starting in mid-2005. From that point forward, the sea level rise has essentially stopped, and appears to be decreasing. Therefore, I plotted out only the data since 2005 (see Figure 2). The linear trend of Figure 2 is +0.23 mm/year, or 23 mm per century. That is barely less than one inch.

But, an even more intriguing aspect exists for Figure 2. There is an upward “bump” in the data in the final six months of 2009, which appears somewhat odd. I referred to this above as a “significant spike” in the data.

Figure 2

Pacific Ocean Basin Mean Sea Level Anomalies and Trend

Since 2005

(click on chart for larger version)

As shown in Figure 3, the “significant spike” was adjusted downward manually. With this adjustment, the linear trend is downward, or (minus) -0.18 mm/year, or 18 mm per century.

Figure 3

Pacific Ocean Basin Mean Sea Level Anomalies and Trend

Since 2005, Adjusted Last Half of 2009

(click on chart for larger version)

In conclusion, the satellite data shows that something significant, something unusual, occurred in the end of 2005. The generally upward trend, slight though it was at approximately 2.6 mm per year, made an abrupt switch. That significant something indicates the ocean levels are no longer increasing. From a climate change perspective, and especially the catastrophic Global Warming predictions, this is an important event.

Roger E. Sowell, Esq.

Marina del Rey, California

Below are the data that was used in the above charts. The first column, "year" shows the year with the week indicated after the decimal. The second column, "msl_ib(mm)" shows the mean sea level (msl) anomaly as measured in millimeters (mm). Where there is a third column, the data is the value after manually subtracting 10 from the mean sea level quantity.

year msl_ib(mm) #version_2011_rel1

1992.9323 -1.486

1992.9595 -5.771

1992.9866 -25.939

1993.0138 -27.168

1993.0409 -31.424

1993.0681 -26.150

1993.0952 -29.214

1993.1223 -17.263

1993.1495 -20.071

1993.1766 -19.212

1993.2038 -16.808

1993.2309 -2.934

1993.2581 -17.298

1993.2852 -11.920

1993.3124 -7.738

1993.3395 -17.114

1993.3667 -19.102

1993.3938 -17.776

1993.4210 -8.777

1993.4481 -11.516

1993.4753 -4.756

1993.5024 -8.066

1993.5296 -8.458

1993.5567 -14.213

1993.5839 -5.229

1993.6110 2.473

1993.6382 -3.918

1993.6653 -8.046

1993.6925 -3.971

1993.7196 -4.677

1993.7468 -2.375

1993.7739 -1.457

1993.8010 -3.732

1993.8282 -2.044

1993.8553 -19.762

1993.8825 -11.975

1993.9096 -2.466

1993.9368 -7.063

1993.9639 -3.717

1993.9911 -10.801

1994.0182 -12.038

1994.0454 -6.875

1994.0725 -5.255

1994.0997 -17.532

1994.1268 -17.331

1994.1540 -28.244

1994.1811 -7.218

1994.2083 -15.977

1994.2354 -7.343

1994.2626 -10.297

1994.2897 -11.519

1994.3169 -9.268

1994.3440 -17.643

1994.3712 -16.789

1994.3983 -25.515

1994.4255 -16.652

1994.4526 -13.122

1994.4798 -21.699

1994.5069 -9.741

1994.5340 2.584

1994.5612 1.977

1994.5883 -6.170

1994.6155 -9.692

1994.6426 -0.417

1994.6698 -5.553

1994.6969 0.574

1994.7241 1.651

1994.7512 -13.184

1994.7784 -13.052

1994.8055 -1.527

1994.8327 -4.111

1994.8598 -3.466

1994.8870 -11.701

1994.9141 -19.910

1994.9413 -12.198

1994.9684 -6.225

1994.9956 -8.456

1995.0227 -12.520

1995.0499 -7.632

1995.0770 2.084

1995.1042 -7.986

1995.1313 -16.003

1995.1585 -20.015

1995.1856 -1.545

1995.2128 1.991

1995.2399 -19.846

1995.2670 -21.026

1995.2942 -18.411

1995.3213 -12.348

1995.3485 -28.584

1995.3756 -23.496

1995.4028 -17.048

1995.4299 -23.640

1995.4571 -18.013

1995.4842 -8.506

1995.5114 -2.396

1995.5657 -11.279

1995.5928 -8.463

1995.6200 -11.265

1995.6471 -6.019

1995.6743 -5.051

1995.7014 2.060

1995.7286 -4.240

1995.7557 -11.793

1995.7829 -2.624

1995.8100 -16.228

1995.8372 -8.110

1995.8643 -7.071

1995.8915 -9.104

1995.9458 -17.448

1995.9729 -14.554

1996.0000 -12.533

1996.0272 -25.578

1996.0543 -21.023

1996.0815 -19.339

1996.1086 -9.820

1996.1358 -4.298

1996.1629 -12.155

1996.1901 -18.272

1996.2172 -17.852

1996.2444 -16.229

1996.2715 -11.495

1996.2987 -5.392

1996.3258 -7.383

1996.3530 -17.568

1996.3801 -15.233

1996.4073 -24.187

1996.4344 -6.655

1996.4616 -10.022

1996.4887 -1.090

1996.5159 -11.351

1996.5430 -3.120

1996.5702 1.027

1996.5973 7.756

1996.6245 -1.135

1996.6516 3.761

1996.6788 6.628

1996.7059 0.862

1996.7330 -0.286

1996.7602 0.077

1996.7873 -12.093

1996.8145 -2.468

1996.8416 2.250

1996.8688 -3.316

1996.8959 -15.110

1996.9231 -7.431

1996.9502 -6.337

1996.9774 -1.417

1997.0045 -8.540

1997.0317 -23.637

1997.0588 -27.977

1997.0860 -7.600

1997.1131 -19.916

1997.1403 2.822

1997.1674 -11.162

1997.1946 -14.802

1997.2217 -13.449

1997.2489 2.620

1997.2760 4.502

1997.3032 -8.379

1997.3303 -9.565

1997.3575 -12.882

1997.3846 -9.367

1997.4118 5.056

1997.4389 0.033

1997.4660 2.361

1997.4932 -0.987

1997.5203 4.889

1997.5475 9.102

1997.5746 22.517

1997.6018 7.607

1997.6289 16.499

1997.6561 7.891

1997.6832 5.615

1997.7104 11.960

1997.7375 28.554

1997.7647 14.698

1997.7918 12.168

1997.8190 9.296

1997.8461 4.881

1997.8733 3.700

1997.9004 9.248

1997.9276 17.072

1997.9547 4.089

1997.9819 7.660

1998.0090 -4.219

1998.0362 1.530

1998.0633 -7.962

1998.0905 7.657

1998.1176 1.009

1998.1448 -3.447

1998.1719 -14.055

1998.1990 -7.810

1998.2262 -2.120

1998.2533 2.024

1998.2805 -5.206

1998.3076 -6.432

1998.3348 -2.764

1998.3619 -15.602

1998.3891 -17.663

1998.4162 6.065

1998.4434 8.740

1998.4705 -6.931

1998.4977 -10.119

1998.5248 -15.512

1998.5520 -10.138

1998.5791 -18.846

1998.6063 1.604

1998.6334 -10.658

1998.6606 -9.011

1998.6877 -6.899

1998.7149 -4.434

1998.7420 6.578

1998.7692 3.433

1998.7963 -23.800

1998.8235 -9.777

1998.8506 -1.830

1998.8777 13.178

1998.9049 0.387

1998.9320 10.445

1998.9592 -13.730

1998.9863 -11.690

1999.0135 -13.324

1999.0406 4.443

1999.0678 -20.479

1999.0949 -8.997

1999.1221 -10.664

1999.1492 -11.500

1999.1764 -4.696

1999.2035 -11.470

1999.2307 19.950

1999.2578 6.461

1999.2850 -12.132

1999.3121 -11.087

1999.3393 -3.948

1999.3664 -9.701

1999.3936 -5.175

1999.4207 1.612

1999.4479 -3.482

1999.4750 -5.375

1999.5022 -3.170

1999.5293 -0.353

1999.5565 11.188

1999.5836 -5.150

1999.6107 -0.195

1999.6379 4.151

1999.6650 -9.725

1999.6922 8.222

1999.7193 14.343

1999.7465 8.878

1999.7736 14.397

1999.8008 8.236

1999.8279 10.616

1999.8551 11.801

1999.8822 8.111

1999.9094 -0.531

1999.9365 -8.548

1999.9637 3.986

1999.9908 4.432

2000.0180 -0.565

2000.0451 -8.416

2000.0723 -6.039

2000.0994 -12.676

2000.1266 -5.719

2000.1537 9.891

2000.1809 4.080

2000.2080 7.529

2000.2352 9.674

2000.2623 -25.511

2000.2895 -3.363

2000.3166 -1.585

2000.3437 6.222

2000.3709 -5.692

2000.3980 -11.024

2000.4252 -8.984

2000.4523 -0.897

2000.4795 7.830

2000.5066 9.358

2000.5338 14.725

2000.5609 -3.741

2000.5881 -3.509

2000.6152 13.350

2000.6424 16.318

2000.6695 15.923

2000.6967 20.860

2000.7238 14.314

2000.7510 16.200

2000.7781 22.300

2000.8053 14.957

2000.8324 13.796

2000.8596 16.710

2000.8867 9.220

2000.9139 17.346

2000.9410 10.647

2000.9682 12.717

2000.9953 14.890

2001.0225 2.224

2001.0496 -4.476

2001.0767 -6.792

2001.1039 1.999

2001.1310 5.674

2001.1582 11.634

2001.1853 4.292

2001.2125 6.119

2001.2396 9.107

2001.2668 9.753

2001.2939 14.194

2001.3211 15.772

2001.3482 2.419

2001.3754 5.291

2001.4025 0.608

2001.4297 4.637

2001.4568 8.147

2001.4840 16.470

2001.5111 16.674

2001.5383 16.058

2001.5654 8.362

2001.5926 22.418

2001.6197 30.018

2001.6469 19.201

2001.6740 15.256

2001.7012 21.082

2001.7283 21.512

2001.7555 22.435

2001.7826 19.299

2001.8097 17.283

2001.8369 14.945

2001.8640 6.213

2001.8912 13.794

2001.9183 13.543

2001.9455 17.139

2001.9726 6.399

2001.9998 0.661

2002.0269 -4.249

2002.0541 3.636

2002.0812 4.086

2002.1084 9.182

2002.1355 8.188

2002.1627 2.279

2002.1898 -0.072

2002.2170 11.181

2002.2441 16.766

2002.2713 20.688

2002.2984 9.809

2002.3256 7.105

2002.3527 8.923

2002.3799 16.298

2002.4070 13.147

2002.4342 13.951

2002.4613 9.205

2002.4885 33.801

2002.5156 32.310

2002.5427 23.925

2002.5699 31.002

2002.5970 20.790

2002.6242 31.008

2002.6513 24.038

2002.6785 20.451

2002.7056 22.940

2002.7328 25.659

2002.7599 28.961

2002.7871 28.605

2002.8142 40.830

2002.8414 28.113

2002.8685 36.796

2002.8957 37.708

2002.9228 31.883

2002.9500 21.026

2002.9771 13.672

2003.0043 17.140

2003.0314 14.896

2003.0586 16.558

2003.0857 23.254

2003.1129 14.095

2003.1400 5.103

2003.1672 15.592

2003.1943 12.493

2003.2214 16.062

2003.2486 17.145

2003.2757 15.688

2003.3029 14.643

2003.3300 -2.371

2003.3572 6.656

2003.3843 21.598

2003.4115 17.099

2003.4386 8.932

2003.4658 0.599

2003.4929 -1.904

2003.5201 14.773

2003.5472 24.663

2003.5744 21.987

2003.6015 22.827

2003.6287 15.495

2003.6558 27.129

2003.6830 34.483

2003.7101 29.843

2003.7373 17.824

2003.7644 22.696

2003.7916 21.445

2003.8187 16.681

2003.8459 16.059

2003.8730 22.121

2003.9002 30.394

2003.9273 24.145

2003.9544 16.364

2003.9816 18.559

2004.0087 16.115

2004.0359 14.764

2004.0630 13.711

2004.0902 13.886

2004.1173 10.665

2004.1445 24.145

2004.1716 24.532

2004.1988 21.958

2004.2259 18.275

2004.2531 25.585

2004.2802 18.355

2004.3074 28.265

2004.3345 6.751

2004.3617 16.021

2004.3888 31.001

2004.4160 17.824

2004.4431 13.313

2004.4703 16.578

2004.4974 27.053

2004.5246 35.658

2004.5517 30.882

2004.5789 20.432

2004.6060 20.551

2004.6332 22.091

2004.6603 27.025

2004.6874 31.066

2004.7146 31.953

2004.7417 22.671

2004.7689 22.977

2004.7960 26.029

2004.8232 25.597

2004.8503 19.157

2004.8775 34.075

2004.9046 19.000

2004.9318 19.071

2004.9589 21.288

2004.9861 22.863

2005.0132 9.980

2005.0404 7.564

2005.0675 17.231

2005.0947 21.605

2005.1218 24.175

2005.1490 27.218

2005.1761 31.271

2005.2033 24.516

2005.2304 1.163

2005.2576 10.944

2005.2847 22.766

2005.3119 8.722

2005.3390 14.094

2005.3662 24.647

2005.3933 18.498

2005.4204 13.527

2005.4476 10.517

2005.4747 28.728

2005.5019 33.957

2005.5290 20.532

2005.5562 26.893

2005.5833 35.955

2005.6105 19.034

2005.6376 20.821

2005.6648 36.776

2005.6919 43.582

2005.7191 35.716

2005.7462 24.423

2005.7734 34.436

2005.8005 42.993

2005.8277 44.890

2005.8548 39.958

2005.8820 41.181

2005.9091 28.913

2005.9363 21.455

2005.9634 32.159

2005.9906 40.387

2006.0177 27.457

2006.0449 15.249

2006.0720 20.739

2006.0992 27.078

2006.1263 24.080

2006.1534 20.989

2006.1806 29.243

2006.2077 14.859

2006.2349 20.911

2006.2620 20.724

2006.2892 26.006

2006.3163 11.493

2006.3435 18.458

2006.3706 14.947

2006.3978 13.771

2006.4249 17.823

2006.4521 21.147

2006.4792 27.871

2006.5064 26.496

2006.5335 24.825

2006.5607 25.118

2006.5878 33.534

2006.6150 30.139

2006.6421 27.590

2006.6693 25.275

2006.6964 29.346

2006.7236 39.852

2006.7507 38.106

2006.7779 36.168

2006.8050 31.744

2006.8321 16.974

2006.8864 31.352

2006.9136 23.923

2006.9407 29.740

2006.9679 23.080

2006.9950 17.493

2007.0222 22.334

2007.0493 16.642

2007.0765 23.088

2007.1036 21.522

2007.1308 23.301

2007.1579 23.528

2007.1851 20.336

2007.2122 14.105

2007.2394 16.908

2007.2665 19.075

2007.2937 28.294

2007.3208 16.378

2007.3480 23.531

2007.3751 18.976

2007.4023 22.323

2007.4294 10.762

2007.4566 23.032

2007.4837 14.731

2007.5109 22.903

2007.5380 18.037

2007.5651 23.751

2007.5923 31.015

2007.6194 30.765

2007.6466 20.630

2007.6737 19.297

2007.7009 27.876

2007.7280 34.705

2007.7552 31.855

2007.7823 25.394

2007.8095 18.442

2007.8366 20.701

2007.8638 34.582

2007.8909 35.878

2007.9181 26.700

2007.9452 21.755

2007.9724 16.414

2007.9995 21.419

2008.0267 27.400

2008.0538 22.421

2008.0810 19.235

2008.1081 9.821

2008.1353 21.663

2008.1624 20.260

2008.1896 20.054

2008.2167 20.441

2008.2439 19.659

2008.2710 25.040

2008.2981 10.276

2008.3253 10.937

2008.3524 20.728

2008.3796 27.421

2008.4067 16.943

2008.4339 24.858

2008.4610 25.867

2008.4882 20.712

2008.5153 20.091

2008.5425 23.795

2008.5696 27.041

2008.5968 34.364

2008.6239 30.966

2008.6511 25.322

2008.6782 33.336

2008.7054 26.113

2008.7325 30.574

2008.7597 24.234

2008.7868 25.791

2008.8140 15.091

2008.8411 17.223

2008.8683 19.665

2008.8954 8.434

2008.9226 27.964

2008.9497 20.110

2008.9769 17.634

2009.0040 26.878

2009.0311 34.380

2009.0583 35.118

2009.0854 9.161

2009.1126 15.858

2009.1397 15.744

2009.1669 16.353

2009.1940 13.617

2009.2212 17.307

2009.2483 25.272

2009.2755 16.205

2009.3026 21.752

2009.3298 28.892

2009.3569 22.549

2009.3841 17.170

2009.4112 12.563

2009.4384 13.766

2009.4655 19.241

2009.4927 20.233

2009.5198 26.375

2009.5470 24.946

2009.5741 46.189 36.189

2009.6013 33.244 23.244

2009.6284 33.593 23.593

2009.6556 45.974 35.974

2009.6827 48.901 38.901

2009.7099 40.834 30.834

2009.7370 48.690 38.690

2009.7642 28.640 18.640

2009.7913 31.518 21.518

2009.8184 33.004 23.004

2009.8456 38.716 28.716

2009.8727 38.035 28.035

2009.8999 34.541 24.541

2009.9270 37.662 27.662

2009.9542 28.762

2009.9813 32.680

2010.0085 32.065

2010.0356 37.049

2010.0628 23.005

2010.0899 23.308

2010.1171 20.713

2010.1442 27.327

2010.1714 25.586

2010.1985 21.481

2010.2257 18.349

2010.2528 27.833

2010.2800 22.848

2010.3071 32.387

2010.3343 27.573

2010.3614 23.300

2010.3886 20.300

2010.4157 20.899

2010.4429 12.568

2010.4700 24.594

2010.4971 14.379

2010.5243 21.078

2010.5514 11.878

2010.5786 29.669

2010.6057 18.464

2010.6329 27.665

2010.6600 22.737

2010.6872 13.456

2010.7143 11.011

2010.7415 23.017

2010.7686 19.647

2010.7958 22.741

2010.8229 27.406

2010.8501 28.889

2010.8772 17.497

2010.9044 15.599

2010.9315 21.153

2010.9587 30.305

2010.9858 22.007

2011.0130 25.324

2011.0401 16.801

2011.0673 19.673