February 21, 2018

Satellites show warming is accelerating sea level rise (?)

Dedicated Warmist Seth Borenstein sets out below a coherent story about warming causing sea-level rise.  He regurgitates all the usual Warmist talking points regardless of their truth.  He says, for instance, that the Antarctic is melting when it is not.

So we have to go back to the journal article behind Seth's splurge to see what the scientists are saying.  I append it below Seth's article.

And what we see there is very different from Seth's confident pronouncements.  We see a very guarded article indeed which rightly lists many of the difficulties in measuring sea level rise.  And they can surmount those difficulties only by a welter of estimates and adjustments.  Anywhere in that process there could be errors and biases.  And as a result, we see that the journal authors describe their findings as only a"preliminary estimate" of sea level rise.

And it gets worse.  When we look further into the journal article we see that the sea level rise is measured in terms of only 64 thousandths of one millimeter.  So we are in the comedy of the absurd.  Such a figure is just a statistical artifact with no observable physical equivalent.

So the sea level rise Seth talks about with great confidence ends up being an unbelievably small quantity measured with great imprecision!  Amazing what you find when you look at the numbers, isn't it?


Melting ice sheets in Greenland and Antarctica are speeding up the already fast pace of sea level rise, new satellite research shows.

At the current rate, the world’s oceans on average will be at least 2 feet higher by the end of the century compared to today, according to researchers who published in Monday’s Proceedings of the National Academies of Sciences.

Sea level rise is caused by warming of the ocean and melting from glaciers and ice sheets. The research, based on 25 years of satellite data, shows that pace has quickened, mainly from the melting of massive ice sheets.

It confirms scientists’ computer simulations and is in line with predictions from the United Nations, which releases regular climate change reports.

"It’s a big deal" because the projected sea level rise is a conservative estimate and it is likely to be higher, said lead author Steve Nerem of the University of Colorado.

Outside scientists said even small changes in sea levels can lead to flooding and erosion. "Any flooding concerns that coastal communities have for 2100 may occur over the next few decades," Oregon State University coastal flooding expert Katy Serafin said.

More than three-quarters of the acceleration of sea level rise since 1993 is due to melting ice sheets in Greenland and Antarctica, the study shows. Of the 3 inches of sea level rise in the past quarter century, about 55 percent is from warmer water expanding, and the rest is from melting ice.

Like weather and climate, there are two factors in sea level rise: year-to-year small rises and falls that are caused by natural events, and larger long-term rising trends that are linked to man-made climate change.

Nerem’s team removed the natural effects of the 1991 Mt. Pinatubo eruption that temporarily chilled Earth and the climate phenomena El Nino and La Nina, and found the accelerating trend.

Sea level rise, more than temperature, is a better gauge of climate change in action, said Anny Cazenave, director of Earth science at the International Space Science Institute in France, who edited the study. Cazenave is one of the pioneers of space-based sea level research.

Global sea levels were stable for about 3,000 years until the 20th century, when they rose and then accelerated due to global warming caused by the burning of coal, oil and natural gas, said climate scientist Stefan Rahmstorf of the Potsdam Institute in Germany, who wasn’t part of the study.

Two feet of sea level rise by the end of the century "would have big effects on places like Miami and New Orleans, but I don’t still view that as catastrophic" because those cities can survive — at great expense — that amount of rising seas under normal situations, Nerem said.

But when a storm like 2012’s Hurricane Sandy hits, sea level rise on top of storm surge can lead to record-setting damage, researchers said.

Some scientists at the American Geophysical Union meeting last year said Antarctica may be melting faster than predicted by Monday’s study.

Greenland has caused three times more sea level rise than Antarctica so far, but ice melt on the southern continent is responsible for more of the acceleration.

"Antarctica seems less stable than we thought a few years ago," Rutgers climate scientist Robert Kopp said.

The reduction of ice in Antarctica has increased the sense of urgency among travelers hoping to see the continent. Tourism in Antarctica has risen from fewer than 2,000 visitors in the 1980s to more than 45,000 visitors from around the world last year.

The number of people traveling to the frozen continent dipped during the economic recession of the late 2000s, but rose again in recent years, according to data kept by the Rhode-Island based International Association of Antarctic Tour Operators.

SOURCE

Climate-change–driven accelerated sea-level rise detected in the altimeter era

By R. S. Nerem et al.

Abstract

Using a 25-y time series of precision satellite altimeter data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3, we estimate the climate-change–driven acceleration of global mean sea level over the last 25 y to be 0.084 ± 0.025 mm/y2. Coupled with the average climate-change–driven rate of sea level rise over these same 25 y of 2.9 mm/y, simple extrapolation of the quadratic implies global mean sea level could rise 65 ± 12 cm by 2100 compared with 2005, roughly in agreement with the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) model projections.

Introduction

Satellite altimeter data collected since 1993 have measured a rise in global mean sea level (GMSL) of ∼3 ± 0.4 mm/y (1, 2), resulting in more than 7 cm of total sea-level rise over the last 25 y. This rate of sea-level rise is expected to accelerate as the melting of the ice sheets and ocean heat content increases as greenhouse gas concentrations rise. Acceleration of sea-level rise over the 20th century has already been inferred from tide-gauge data (3⇓–5), although sampling and data issues preclude a precise quantification. The satellite altimeter record of sea-level change from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 is now approaching 25 y in length, making it possible to begin probing the record for climate-change–driven acceleration of the rate of GMSL change (6). Unlike tide-gauge data, these retrievals sample the open ocean and allow for precise quantitative statements regarding global sea level. However, detecting acceleration is difficult because of (i) interannual variability in GMSL largely driven by changes in terrestrial water storage (TWS) (7⇓–9), (ii) decadal variability in TWS (10), thermosteric sea level, and ice sheet mass loss (11) that might masquerade as a long-term acceleration over a 25-y record, (iii) episodic variability driven by large volcanic eruptions (12), and (iv) errors in the altimeter data, in particular, potential drifts in the instruments over time (13). With careful attention to each of these issues, however, a preliminary satellite-based estimate of the climate-change–driven acceleration of sea-level rise can be obtained. This estimate is useful for understanding how the Earth is responding to warming, and thus better informs us of how it might change in the future.

SOURCE





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