You know, I would have a lot less trouble believing climate scientists could actually measure changes
in global average sea level to within a milimeter, if I didn't know how badly they overstate their confidence in «global average temperature» in all its many manifestations, with all its many assumptions, models and WAGs.
Sea level equivalent (SLE)- The change
in global average sea level that would occur if a given amount of water or ice were added to or removed from the oceans.
► Eustatic sea - level rise is a change
in global average sea level brought about by an increase in the volume of the world ocean.
Not exact matches
Sea levels in Japan will rise 10 to 20 % faster than the
global average.
We have much better — and more conclusive — evidence for climate change from more boring sources like
global temperature
averages, or the extent of
global sea ice, or thousands of years» worth of C02
levels stored frozen
in ice cores.
It also reviews recent scientific literature on «worst - case»
global average sea -
level projections and on the potential for rapid ice melt
in Greenland and Antarctica.
Of course, while short - term changes
in sea level can be predicted fairly accurately based on the motions of the moon and sun, it is a lot harder predicting the ups and downs of the
average global surface temperature — there is a lot of noise, or natural variation,
in the system.
But
in mid-2010, scientists noticed a curious trend: For the first time
in two decades,
global average sea level began dropping.
The reduction
in the ice mass has contributed to
global average sea -
level rise of 25 millimeters.
But skyrocketing Arctic temperatures, which are rising twice as fast as the
global average, have set off a downward spiral
in sea ice
levels.
Exactly how much the
average global sea level will rise
in the future will depend on our greenhouse gas emissions.
In August
global sea surface temperatures reached record
levels — the
average temperature was 1.17 degrees Fahrenheit higher than the 20th century
average.
Third, using a «semi-empirical» statistical model calibrated to the relationship between temperature and
global sea -
level change over the last 2000 years, we find that,
in alternative histories
in which the 20th century did not exceed the
average temperature over 500-1800 CE,
global sea -
level rise
in the 20th century would (with > 95 % probability) have been less than 51 % of its observed value.
For a future of continued growth
in emissions the new results indicate a likely
global average sea -
level rise between 1.1 and 2.1 meters (3.6 to 6.9 feet)-- roughly double the IPCC - consistent estimate.
One recent modeling study focused on this mode of instability estimated that the Antarctic ice sheet has a 1 -
in - 20 chance of contributing about 30 centimeters (1.0 feet) to
global average sea -
level rise over the course of this century and 72 centimeters (2.4 feet) by the end of the next century.
Regardless of emissions pathway and approach, there is likely to be between about 16 and 40 cm (0.5 and 1.3 feet) of
global average sea -
level rise
in the first half of the century.
The Fourth Assessment Report finds that «Warming of the climate system is unequivocal, as is now evident from observations of increases
in global average air and ocean temperatures, widespread melting of snow and ice, and rising mean
sea level.
Imagine
sea levels rising by feet instead of inches,
global average temperatures increasing by many degrees instead of just fractions and an increase
in other cataclysmic, costly and fatal weather events.
«These new results indicate that relative
sea levels in New Zealand have been rising at an
average rate of 1.6 mm / yr over the last 100 years — a figure that is not only within the error bounds of the original determination, but when corrected for glacial - isostatic effects has a high
level of coherency with other regional and
global sea level rise determinations.
But the
global average rise
in sea level is a chimera of many factors acting differently at various locations.
You need longer - term
averaging in order to be looking at the true
global sea -
level signal, rather than sampling noise.
«suggesting that Arctic warming will continue to greatly exceed the
global average over the coming century, with concomitant reductions
in terrestrial ice masses and, consequently, an increasing rate of
sea level rise.»
Many recent studies (e.g. Hansen & Sato) have claimed that future rise
in global average temperature (GAT) will create a much greater effect on
sea level than IPCC AR4 predicts.
The increase
in these winds has caused eastern tropical Pacific cooling, amplified the Californian drought, accelerated
sea level rise three times faster than the
global average in the Western Pacific and has slowed the rise of
global average surface temperatures since 2001.
Regarding the «
global ice at 1980
levels», here is the canned response we wrote
in rebuttal to the astonishingly twisted piece
in Daily Tech: What the graph shows is that the
global sea ice area for early January 2009 is on the long term
average (zero anomaly).
Warming of the climate system is unequivocal, as is now evident from observations of increases
in global average air and ocean temperatures, widespread melting of snow and ice, and rising
global average sea level.
For example, if this contribution were to grow linearly with
global average temperature change, the upper ranges of
sea level rise for SRES scenarios shown
in Table SPM - 3 would increase by 0.1 m to 0.2 m. Larger values can not be excluded, but understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for
sea level rise.
Sea levels in the Philippines are rising at about twice the
global average.
However, careful selection of tide gauge sites such that records reflecting major tectonic activity are rejected, and
averaging over all selected gauges, results
in a small uncertainty for
global sea level estimates (Appendix 5.
For example, the latest (fifth) assessment report from the U.N.'s Intergovernmental Panel on Climate Change (IPCC) projects that the
global average sea level rise over the course of the 21st century would be
in the range of 10 to 32 inches, with a mean value of about 19 inches.
According to Professor Nils - Axel Mörner, who has written more than 600 learned papers
in his 50 - year career studying
sea level,
global average sea level may not be rising at all at the moment.
It found eight of the atolls and almost three - quarters of the islands grew during the study period, lifting Tuvalu's total land area by 2.9 percent, even though
sea levels in the country rose at twice the
global average.
Each base's exposure is calculated based on the National Climate Assessment's midrange or «intermediate - high»
sea level rise scenario (referred to
in this analysis as «intermediate»), which projects a
global average increase of 3.7 feet above 2012
levels, by 2100; and a «highest» scenario based on a more rapid rate of increase, which projects a
global average increase of 6.3 feet.
In fact, since then, greenhouse gas emissions have continued to rise, and accordingly
global average temperatures have steadily increased, along with
sea levels.
Although the IPCC climate models have performed remarkably well
in projecting
average global surface temperature warming thus far, Rahmstorf et al. (2012) found that the IPCC underestimated
global average sea level rise since 1993 by 60 %.
Looking deeper
in time,
global climate was an
average of 2 to 3 degrees warmer than at present some 3 million years ago, and
sea levels were 35 ± 18 m above the shoreline of today.
We might expect «
global warming» (i.e., an increase
in average surface air temperatures over a few decades) to lead to a rise
in global mean
sea levels.
In her role, she ensures that all program analyses reflect robust and relevant climate science, and researches the influence of major carbon producers on rising
global average temperatures and
sea level.
As you are aware there are major local variations from the
global pattern, with coastal land
in some regions sinking faster than the
average and
in other regions being uplifted with respect to mean
sea level.
Global average temperatures were between 5.4 and 7.2 degrees Fahrenheit (3 to 4 degrees Celsius) higher than today, and
sea level was as much as 131 feet (40 meters) higher
in some places.
By the late 21st century, climate models project that
sea level will rise up to a foot higher than the
global average along the northeast US coastline, resulting
in a dramatic increase
in regional coastal flood risk.
Global average sea levels have risen by around 3.2 mm per year since satellite measurements began
in 1993, the report says, with
sea levels around 67 mm higher
in 2014 than they were
in 1993.
Sea - level projections by the Intergovernmental Panel on Climate Change (IPCC), by our research group and by others indicate that global average sea level at the end of the century would likely be about 1 - 2.5 feet higher under the Paris path than in 20
Sea -
level projections by the Intergovernmental Panel on Climate Change (IPCC), by our research group and by others indicate that
global average sea level at the end of the century would likely be about 1 - 2.5 feet higher under the Paris path than in 20
sea level at the end of the century would likely be about 1 - 2.5 feet higher under the Paris path than
in 2000.
Both the observations of mass balance and the estimates based on temperature changes (Table 11.4) indicate a reduction of mass of glaciers and ice caps
in the recent past, giving a contribution to
global -
average sea level of 0.2 to 0.4 mm / yr over the last hundred years.
From this it can be seen that
in some places
sea level trend is rising whilst
in others it is falling, so giving a
global average disguises the nuances of what is happening locally, where it matters.
Global sea level averaged over the decade was about 20 cm higher than
in 1880, the report says.
Boutrous pointed out that while
global sea levels are rising on
average, some evidence shows that
sea levels have fallen
in specific regions, and coastal flooding
in places like the San Francisco Bay Area is also a function of local conditions like land subsidence.
Global average sea level is expected to continue to rise by at least several inches
in the next 15 years and by 1 — 4 feet by 2100.
The Fourth Assessment Report finds that «Warming of the climate system is unequivocal, as is now evident from observations of increases
in global average air and ocean temperatures, widespread melting of snow and ice, and rising mean
sea level.
«Our results from this study imply that if future anthropogenic warming effects
in the Indo - Pacific warm pool dominate natural variability, mid-ocean islands such as the Mascarenhas Archipelago, coasts of Indonesia, Sumatra, and the north Indian Ocean may experience significantly more
sea level rise than the
global average,» Han said.