lolwot «It logically follows then that the same global
sea level trend in recent years also suggests substantial thermal expansion.»
They find it to be biased high, although the obtained
sea level trend in this case is lower than in the real Church & White reconstruction and fully encompasses the hypothetical «true» range.
«[B] y making use of 21 CMIP5 coupled climate models, we study the contribution of external forcing to the Pacific Ocean regional sea level variability over 1993 — 2013, and show that according to climate models, externally forced and thereby the anthropogenic sea level fingerprint on regional
sea level trends in the tropical Pacific is still too small to be observable by satellite altimetry.»
Searches the lower bounds of statistically significant external
sea level trends in longest tidal records worldwide
The east - west contrast of
sea level trends in the Pacific observed since the early 1990s can not be satisfactorily accounted for by climate models, nor yet definitively attributed either to unforced variability or forced climate change.
Yes, the first Table (Recent short - term
sea level trends in the Project area based upon SEAFRAME data through September 2006) lists trends of 2.7 to 17 mm / yr.
Not exact matches
Beyond honing communications skills, participants said while the discussions often started off with broad
trends in climate science, invariably the exchanges shifted to specific local issues such as wildfires, ozone
levels, crop rotations,
sea level rise, droughts and air quality.
John Fasullo of the National Center for Atmospheric Research
in Boulder, Colorado, noticed something amiss while looking at
trends in global
sea levels.
Sea -
level rise and coral bleaching often dominate discussions about how climate change affects the ocean, but a host of more subtle — and harder to research —
trends also play a role
in reshaping the world's marine ecosystems.
Just as the underlying change
in sea level is swamped by the daily and monthly changes, so the annual variation
in global temperature masks any underlying
trends.
But
in mid-2010, scientists noticed a curious
trend: For the first time
in two decades, global average
sea level began dropping.
If the
trend continues, ice sheets could become the dominant contributor to
sea level rise sooner than scientists had predicted, concludes the research, which will be published this month
in the journal Geophysical Research Letters.
«Every time some unexpected change
in any climate parameter happens (e.g.,
sea level going down), the question will be raised on whether this will be a continuing
trend.
But this year, a big spring meltdown
in October and November suddenly reversed that
trend and has led to continued record low
sea ice
levels as the summer melt season progressed.
This decreasing
trend in local gravity is sufficient to counteract all other sources of local
sea -
level rise.
Throughout the altimeter era, it has been recognized that
sea level rise is not constant but varies considerably about the background
trend, with the largest of these departures coinciding with the warm and cold phases of the El Niño Southern Oscillation (ENSO) such as
in 1997 — 1998 (Fig. 2).
The increase
in rate relative to the 1901 — 90
trend is accordingly larger than previously thought; this revision may affect some projections11 of future
sea -
level rise.
So far, the climate science used
in courts has focused mostly on overall
trends and gradual processes such as
sea level rise, said Michael Burger, executive director of the Sabin Center for Climate Change Law at Columbia Law School
in New York, who said he has no financial stake
in climate change litigation.
When you add
in climate
trends including
sea level rise, which can increase the height of storm surge, and projections of fewer but more intense hurricanes, you have a recipe for increased vulnerability and losses
in these regions
in the future.
Dr. Jonathan Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona, and recipient of the shared 2007 Nobel Peace Prize for his role as a Coordinating Lead Author for the UN Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment, will address the
trend of droughts
in the west and the vulnerability of coastal communities as they face
sea level rise coupled with increasing storm intensities.
Despite their inability to help individual learners at the primary and secondary
levels, success data can provide valuable information to
SEAs, LEAs, and schools regarding the long - terms
trends in learner performance and institutional effectiveness.
1) The observed JASON1 + JASON2
sea level rise given
in the table is 1.6 mm / yr, which is only 66 % of the actual JASON1 + JASON2
trend of 2.4 mm / yr over the same period.
If this
trend is not halted soon, many millions of people will be at risk from extreme events such as heat waves, drought, floods and storms, our coasts and cities will be threatened by rising
sea levels, and many ecosystems, plants and animal species will be
in serious danger of extinction.
After over a year of sideways and downward movement from late 2015 through early 2017, the most recent NASA report shows that over the past year an acceleration
in sea level rise has become visible on the NASA graph, even with just a quick glance (then again, while the long term
trend is consistently upward, the annual
trend is so variable, that it's likely foolish on my part to suggest a change
in trend based on the most recent periods of increase which have only been occurring for less than 12 months).
Dr. Jonathan Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona, and recipient of the shared 2007 Nobel Peace Prize for his role as a Coordinating Lead Author for the UN Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment, will address the
trend of droughts
in the west and the vulnerability of coastal communities as they face
sea level rise coupled with increasing storm intensities.
I focused on Fig 2 of Rahmstorf 2012, which shows the rate of
sea level change
in the form of 10 yr decadal
trends.
Several magnetic susceptibility phases and
trends are recognised and are interpreted
in terms of
sea -
level fluctuations before, during and after the PETM.
You'll need to use the Victor Mark One Eyeball to convince yourself there's no change or
trend in sea level there.
Note that the variation
in sea level due to ENSO is only a few mm, really small compared to both the longer - term anthropogenic
trend and to the local variations
in sea level in the Pacific which can be even decimetres
in places.
In fact when there is a year of heavy flooding, drainage can't keep up and
sea level drops, but this variation is superimposed on the long term
trend of rising
seas.
Holgate (2007) showed decadal rates of
sea -
level rise (linear
trends over 10 years), but as we have shown
in Rahmstorf et al. (2012), those vary wildly over time simply as a result of sampling noise and are not consistent across different data sets (see Fig. 2 of our paper).
[Aug. 9, 8:04 p.m. Updated Joe Romm has predictably assailed my view of Arctic
sea ice
trends and their implications, straying into discussions of melting permafrost (which is an entirely different issue laden with its own questions — one being why the last big retreat of permafrost,
in the Holocene's warmest stretch, didn't have a greenhouse - gas impact) and my refusal to proclaim a magically safe
level of carbon dioxide (which I discuss here).
There is no substantive
trend — whereas both GRACE and Jason are showing positive
trends in mass and
sea level respectively.
You'll undoubtedly hear from some folks who question whether Maldives is threatened by rising
seas by pointing to scientific controversies over recent
sea -
level trends in the Indian Ocean, so I'll put up a link to relevant published literature on Google Scholar here.
[Response: Current
trends in sea level rise are larger (> 3mm / year), and estimates of future changes rely on more that the excel linear regression routine.
Here are some possible choices —
in order of increasing sophistication: * All (or most) scientists agree (the principal Gore argument) * The 20th century is the warmest
in 1000 years (the «hockeystick» argument) * Glaciers are melting,
sea ice is shrinking, polar bears are in danger, etc * Correlation — both CO2 and temperature are increasing * Sea levels are rising * Models using both natural and human forcing accurately reproduce the detailed behavior of 20th century global temperature * Modeled and observed PATTERNS of temperature trends («fingerprints») of the past 30 years ag
sea ice is shrinking, polar bears are
in danger, etc * Correlation — both CO2 and temperature are increasing *
Sea levels are rising * Models using both natural and human forcing accurately reproduce the detailed behavior of 20th century global temperature * Modeled and observed PATTERNS of temperature trends («fingerprints») of the past 30 years ag
Sea levels are rising * Models using both natural and human forcing accurately reproduce the detailed behavior of 20th century global temperature * Modeled and observed PATTERNS of temperature
trends («fingerprints») of the past 30 years agree
If those
trends continue, it puts the world on track for the highest predicted rises
in temperature and
sea level.
Here we analyze a series of climate model experiments along with observational data to show that the recent warming
trend in Atlantic
sea surface temperature and the corresponding trans - basin displacements of the main atmospheric pressure centers were key drivers of the observed Walker circulation intensification, eastern Pacific cooling, North American rainfall
trends and western Pacific
sea -
level rise.
Global
trends in sea level from these gauges are between 1.7 to 2.4 mm / yr.
-- It is very likely that average
sea level rise will contribute to upward
trends in extreme
sea levels in extreme coastal high water
levels.
Residents of Fire Island, N.Y., will find no comfort
in a new study on
sea level trends.
Patrick Henry says: «According to Aviso, current
sea level rise rates are 24cm / century, and the second derivative of the six year
trend is negative — suggesting that 24 cm number will get smaller
in the near future.»
Most scientists accept we are
in a warming
trend, that ice is melting,
sea levels are rising, etc..
But it's also clear that more science clarifying overall
trends in temperature over a mostly sub-zero continent will have little bearing on what societies choose to do, or not do, related to accumulating greenhouse gases, warming and the resulting rise
in sea levels.
The realities of
sea -
level rise and Antarctic
trends and China's emissions, etc., make me feel ever more confident that the [bend, stretch, reach, teach] shift I charted for my goals
in my TEDx talk (away from numbers and toward qualities) is the right path.
A point about
sea -
level:
in this discussion (off topic), many consider that recent and short term
trends measured by T - P or Jason can be extrapolated to the whole 21st century, and some even sugest an exponential rise.
Joe Romm has predictably assailed my rejection of his «death spiral» depiction of Arctic
sea ice
trends, straying into discussions of melting permafrost (which is an entirely different issue laden with its own questions — one being why the last big retreat of permafrost,
in the Holocene's warmest stretch, didn't have a greenhouse - gas impact) and my refusal to proclaim a magically safe
level of carbon dioxide (which I discuss here).
Here's how the summary put it: «The June 2010 Outlook indicates a continuation of the overall
trend in long - term loss of summer Arctic
sea ice, with no indication that a return to historical
levels of the 1980s / 1990s will occur.»
But looking at the diagram, despite the seasonal variation would seem to be positive
trend in the mass component for
sea level.
This has far greater economic impact than some small
trend in sea level which we can accommodate over time.