Actual Sea Level Data Confirms Climate Modelling

[Occams Barber]

Sea level data confirms climate modeling projections were right
by Lachlan Gilbert, University of New South Wales

The IPCC says sea levels could rise around 30-60 cm by 2100 even if greenhouse gas emissions are sharply reduced and global warming is limited to well below 2°C, but around 60-110 cm if greenhouse gas emissions continue to increase strongly. Credit: go_greener_oz, licensed under CC BY-ND 2.0

Projections of rising sea levels this century are on the money when tested against satellite and tide-gauge observations, scientists find.

Climate model projections of sea-level rises in the early 21st century are in good agreement with sea level data recorded in the corresponding period, a recent analysis has found.

And the scientists who crunched the numbers say the finding does not bode well for sea level impacts over coming decades if greenhouse gas emissions are not reined in.

In an article published recently in Nature Communications, the scientists from Chinese and Australian institutions including UNSW Sydney examined the global and regional sea level projections of two reports by the Intergovernmental Panel on Climate Change: the Fifth Assessment Report (AR5) and Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC).

They compared the reports' projections with the observed global and coastal sea level data gathered from satellites and a network of 177 tide-gauges from the start of the projections in 2007 up to to 2018. The scientists found that the trends of the AR5 and SROCC sea level projections under three different scenarios of greenhouse gas emissions "agree well with satellite and tide-gauge observations over the common period 2007–2018, within the 90 percent confidence level."

More:
Sea level data confirms climate modeling projections were right (phys.org)

OB
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[OldWiseGuy]

Invest in sandbags.

 

[Quid est Veritas?]

Coastlines change. During the Roman warm period and Mediaeval warm period, most of the Fens in Britain were underwater; and places like Adria were seaports (after which the Adriatic Sea is named, and now 24 km inland). Granted there are other factors like silting and glacial tilting, but warming will alter them. We are still colder than those previous warm periods, when Romans planted grapes in Britain and the Norse grew wheat in Greenland. Humans will adapt. We should just prepare to abandon very low lying areas, or start building dykes if economically feasible.

That said, it is encouraging these models are better, but many others were way off. According to Al Gore, Florida should be gone by now, for instance. There are always more conservative and more extreme modelling, and only after the fact could we really see.

 

[DamianWarS]

Coastlines change. During the Roman warm period and Mediaeval warm period, most of the Fens in Britain were underwater; and places like Adria were seaports (after which the Adriatic Sea is named, and now 24 km inland). Granted there are other factors like silting and glacial tilting, but warming will alter them. We are still colder than those previous warm periods, when Romans planted grapes in Britain and the Norse grew wheat in Greenland. Humans will adapt. We should just prepare to abandon very low lying areas, or start building dykes if economically feasible.

That said, it is encouraging these models are better, but many others were way off. According to Al Gore, Florida should be gone by now, for instance. There are always more conservative and more extreme modelling, and only after the fact could we really see.

 

[Quid est Veritas?]

View attachment 295007

View attachment 295008

I don't understand your graph. It is mapping Temperature Anomalies and not Temperature. How on earth was that quantified? How did they decide a baseline, then? Further, how could they specify so much of the world's ocean temperature, if most of our knowledge does not go further back in that regard than the Challenger expedition in the 19th century? The only reason we can map the temperature otherwise was based on Greenland ice cores and the effects on ocean temperature on Icelandic glaciers, and it is still nowhere near the temperatures back then. I suspect the mediaeval graph has a red spot in the North Atlantic based on the Ice cores, but from whence does it get the rest? Looks very dubious to my mind.

Medieval Warm Period - an overview | ScienceDirect Topics

 

[OldWiseGuy]

Coastlines change. During the Roman warm period and Mediaeval warm period, most of the Fens in Britain were underwater; and places like Adria were seaports (after which the Adriatic Sea is named, and now 24 km inland). Granted there are other factors like silting and glacial tilting, but warming will alter them. We are still colder than those previous warm periods, when Romans planted grapes in Britain and the Norse grew wheat in Greenland. Humans will adapt. We should just prepare to abandon very low lying areas, or start building dykes if economically feasible.

That said, it is encouraging these models are better, but many others were way off. According to Al Gore, Florida should be gone by now, for instance. There are always more conservative and more extreme modelling, and only after the fact could we really see.

The problem is overpopulation, many of which live near coastal areas. The displacement of these populations would be catastrophic.

"Today (2003), approximately 3 billion people — about half of the world’s population — live within 200 kilometers of a coastline. By 2025, that figure is likely to double."

Ripple Effects: Population and Coastal Regions – Population Reference Bureau

This isn't funny.

 

[DamianWarS]

I don't understand your graph. It is mapping Temperature Anomalies and not Temperature. How on earth was that quantified? How did they decide a baseline, then? Further, how could they specify so much of the world's ocean temperature, if most of our knowledge does not go further back in that regard than the Challenger expedition in the 19th century? The only reason we can map the temperature otherwise was based on Greenland ice cores and the effects on ocean temperature on Icelandic glaciers, and it is still nowhere near the temperatures back then. I suspect the mediaeval graph has a red spot in the North Atlantic based on the Ice cores, but from whence does it get the rest? Looks very dubious to my mind.

Medieval Warm Period - an overview | ScienceDirect Topics

I think you understand the graph fine but you don't know how the data was collected (the source is here). the medieval warm period (MWP) was a temperature anomaly for the North Atlantic coastal regions. As westerners we tend to be predisposed to western vacuums where the only thing that is important happens in our corner of the world, then we superimpose this over the rest of the world. because the MWP affected coastal regions of the then "west" we use this data to claim it as a global event because nothing else enters our peripheral vision. But the WMP was not a global event it was a regional anomaly so we shouldn't use it to debunk global events as it doesn't fit that pattern.

 

[DamianWarS]

The problem is overpopulation, many of which live near coastal areas. The displacement of these populations would be catastrophic.

David Attenborough advice to help slow or reverse climate change is to have smaller families which would reduce our personal impact on the globe. If I have 4 kids, and each of my kids has 4 kids and each of those kids has 4 kids we are looking at 84 humans that may be living at the same time having an impact on the globe. Where If I have 2 kids, and each of my kids has 2 kids and each of those kids has 2 kids then the total is 14 humans possibly living at the same time that have an impact on the globe. (if it was 3x3x3 it would be 39 humans and 1x1x1 would be 3 humans). probably not all your kids will have 4 kids but you can see the sort of impact it can have if we value small families over large ones and it is a simple plan that we all can do.

 

[OldWiseGuy]

David Attenborough advice to help slow or reverse climate change is to have smaller families which would reduce our personal impact on the globe. If I have 4 kids, and each of my kids has 4 kids and each of those kids has 4 kids we are looking at 84 humans that may be living at the same having an impact on the globe. Where If I have 2 kids, and each of my kids has 2 kids and each of those kids has 2 kids then the total is 14 humans possibly living at the same time that have an impact on the globe. (if it was 3x3x3 it would be 39 humans and 1x1x1 would be 3 humans). probably not all your kids will have 4 kids but you can see the sort of impact it can have if we value small families over large ones and it is a simple plan that we all can do.

My extended family is not reproducing much at all.

Me-2 children

My son-2 kids
My daughter-1 kid

My brother-2 children

His son-none
His daughter-none

My sister- 2 children

Her son-none
Other son-none

So between myself, my sister and brother (and spouses) we have produced 6 children, basically only replacing ourselves.

Those 6, all adults, have (and only will) produced 3 more people. So they have reduced the family by 50 percent (when they pass on).

Of the original 6 (includes spouses) only three of us are still living, and we are nearing the end.

 

[DamianWarS]

My extended family is not reproducing much at all.

Me-2 children

My son-2 kids
My daughter-1 kid

My brother-2 children

His son-none
His daughter-none

My sister- 2 children

Her son-none
Other son-none

So between myself, my sister and brother (and spouses) we have produced 6 children, basically only replacing ourselves.

Those 6, all adults, have (and only will) produced 3 more people. So they have reduced the family by 50 percent (when they pass on).

Of the original 6 (includes spouses) only three of us are still living, and we are nearing the end.

Western culture has shifted to smaller families where war time era and subsequent economic booms seems to value larger families. Many of those are still alive and still impacting the globe but in 20-30 years those individuals will have passed on. Declining population is never good for the economy and places like Canada try to ramp up immigration so they can continue to have healthy growth. So places like Canada have strategic population growth for planned healthy economy.

But I'm not sure what sort of impact this has in the countries looking to immigrate to western places as increased people heading out leaves empty spots behind. These available spots may allow someone without a job to have a job or get a better paying job and get better skills. It also may produce a greater amount of income sent from immigrated families back to their home countries. Generally this may increase standards which is good for education, health and the economy all round. Increase standards is a good thing and it will have a product of healthier people living longer and increased sizes of families as is common in economic booms.

These are of course encouraging and good things for those countries but the not so silver lining is that the global population may not be able to slow and will continue to increase toward these unsustainable levels.

 

[OldWiseGuy]

Most growth isn't "healthy growth", just the opposite.

 

[Quid est Veritas?]

I think you understand the graph fine but you don't know how the data was collected (the source is here). the medieval warm period (MWP) was a temperature anomaly for the North Atlantic coastal regions. As westerners we tend to be predisposed to western vacuums where the only thing that is important happens in our corner of the world, then we superimpose this over the rest of the world. because the MWP affected coastal regions of the then "west" we use this data to claim it as a global event because nothing else enters our peripheral vision. But the WMP was not a global event it was a regional anomaly so we shouldn't use it to debunk global events as it doesn't fit that pattern.

Don't go tilting at windmills. No one is using the Mediaeval Warm Period to debunk anything. Your source is wrong though, and based on its obvious partisan stance, dubious. To quote from the article on the Mediaeval warm period I linked earlier:

Historical accounts confirm the worldwide occurrence of the MWP. It was a time of warm climate from about 900 AD to 1300 AD. Its effects were evident in Europe, where grain crops flourished, alpine tree lines rose, many new cities arose, and the population more than doubled. The Vikings took advantage of the climatic amelioration to colonize Greenland, and wine grapes were grown as far north as England, where growing grapes is now not feasible, and about 500 km north of present vineyards in France and Germany. Grapes are presently grown in Germany up to elevations of about 560 m, but from about 1100 AD to 1300 AD., vineyards extended up to 780 m, implying temperatures warmer by about 1.0–1.4°C. Wheat and oats were grown around Trondheim, Norway, suggesting climates about 1°C warmer than present (Fagan, 2000).

Elsewhere in the world, prolonged droughts affected the southwestern United States and Alaska warmed. Sediments in central Japan record warmer temperatures. Sea surface temperatures in the Sargasso Sea were approximately 1°C warmer than today (Keigwin, 1996), and the climate in equatorial east Africa was drier from 1000 AD to 1270 AD. An ice core from the eastern Antarctic Peninsula shows warmer temperatures during this period.

Oxygen isotope studies in Greenland, Ireland, Germany, Switzerland, Tibet, China, New Zealand, and elsewhere, plus tree-ring data from many sites around the world, all confirm the existence of a global MWP. Soon and Baliunas (2003) found that 92% of 112 studies showed physical evidence of the MWP, only 2 showed no evidence, and 21 of 22 studies in the Southern Hemisphere showed evidence of Medieval warming. Evidence of the MWP at specific sites is summarized in Fagan (2007) and Singer and Avery (2007).

They even mention Mann's studies there, and point out why they are flawed. People want to make the Mediaeval and Roman warm periods into false things or regional ones, only because people who deny manmade climate change latched on to them. This is merely another type of disinformation. The world is warming faster than it should, but the climate has never been static, and we have been in a warming cycle from the 1700 by any measure. Besides, one of the big threats of global warming is the decreased arctic sea ice and Greenland ice-caps with decreased reflection of solar radiation and thus a warming effect, so to call the Mediaeval Warm Period merely regional undermines that argument, as it should have resulted in a global warming then anyway.

I am not a climatologist though, but am deferring to other climatologists. The historic accounts suggest warmer temperatures though, with later planting seasons and crops grown in higher latitudes. We still can't grow wheat in Greenland, so even if it was regional, the temperatures were higher there. Also the sea levels globally, which was the point of the post. We'll adapt, even if some areas might need to be abandoned. That is what humans do.

 

[Quid est Veritas?]

David Attenborough advice to help slow or reverse climate change is to have smaller families which would reduce our personal impact on the globe. If I have 4 kids, and each of my kids has 4 kids and each of those kids has 4 kids we are looking at 84 humans that may be living at the same time having an impact on the globe. Where If I have 2 kids, and each of my kids has 2 kids and each of those kids has 2 kids then the total is 14 humans possibly living at the same time that have an impact on the globe. (if it was 3x3x3 it would be 39 humans and 1x1x1 would be 3 humans). probably not all your kids will have 4 kids but you can see the sort of impact it can have if we value small families over large ones and it is a simple plan that we all can do.

I think this misses the point. The vast majority of human activity is done by a tiny percentage. 1% produces more carbon than the lower 50% combined.

Climate change: Global 'elite' will need to slash high-carbon lifestyles

If you really want to alter it, the answer is Austerity. Going on global vacations, air conditioning everywhere, using the internet, mining bitcoin, that sort of thing. These things produce far more heat and carbon, and need not be big families. In fact, smaller families have more excess income which others might have spent on things like schooling, to indulge in such high-waste practices. I certainly am travelling less and such, having had kids. So for all we know, this might worsen the problem. It seems obvious to say less people means less damage, but the rate of our insistance on consumerism and such, that is not necessarily the case.

 

[Quid est Veritas?]

The problem is overpopulation, many of which live near coastal areas. The displacement of these populations would be catastrophic.

"Today (2003), approximately 3 billion people — about half of the world’s population — live within 200 kilometers of a coastline. By 2025, that figure is likely to double."

Ripple Effects: Population and Coastal Regions – Population Reference Bureau

This isn't funny.

How do we know there is overpopulation? We produce more than enough to feed everyone, distribution is just poor. We could probably feed more.

Feeding the world without wrecking the planet is possible

We could probably plan human population growth better, but it is just an a priori assumption to say we are overpopulated. Large swathes of the globe is still empty, we just insist on congregating on tiny bits of it. Further, global warming will help open areas of Canada and Siberia to profitable economic activity that were previously not feasible, or some argue the warmer temperatures might strengthen monsoons helping to wet the Sahel (less convinced on that one), so arguably, land under cultivation might increase. It was for this reason that people talked about purposefully warming the world, back in the early 20th century (during the era of great futurist geo-engineering dreams, like Atlantropa to dam the Mediterranean or the rush to build dams everywhere).

Personally, we should look at something like Green Mountain the British made on Ascension. I think artificially created eco-systems are probably the way to go. Adapt to the new conditions. Build dykes or polders, or resettle - whichever is more economically or politically feasible.

 

[OldWiseGuy]

How do we know there is overpopulation? We produce more than enough to feed everyone, distribution is just poor. We could probably feed more.

Feeding the world without wrecking the planet is possible

We could probably plan human population growth better, but it is just an a priori assumption to say we are overpopulated. Large swathes of the globe is still empty, we just insist on congregating on tiny bits of it. Further, global warming will help open areas of Canada and Siberia to profitable economic activity that were previously not feasible, or some argue the warmer temperatures might strengthen monsoons helping to wet the Sahel (less convinced on that one), so arguably, land under cultivation might increase. It was for this reason that people talked about purposefully warming the world, back in the early 20th century (during the era of great futurist geo-engineering dreams, like Atlantropa to dam the Mediterranean or the rush to build dams everywhere).

Personally, we should look at something like Green Mountain the British made on Ascension. I think artificially created eco-systems are probably the way to go. Adapt to the new conditions. Build dykes or polders, or resettle - whichever is more economically or politically feasible.

People have a habit of gathering in large cities. That won't change.

More people means more cultivation of land, a major cause of climate change.