A question has arisen from ongoing independent general research into world ocean ecosystem devastation and seafood-dependent islander under-nutrition, and solutions.

What percentage of melted polar and glacier ice water evaporates into atmosphere and cloud instead of adding to AGW sea level rise?

JFAus

Ian Plimer has all the answers to the weather/climate/CO2/disappearing islands under the sea hoax.

His latest book 'Heaven And Earth. Global warming. The missing science' is a good read.

The missing science is geology, which records all the natural climate changes that have occurred over time.

Geology is the one way to integrate all aspects of the environment - but there is still little or no geological input into discussion about climate change. Nor do history and archaeology get a look in.

. Climate has always changed and always will
. Sea levels, ditto
. Ice sheets come and go
. Climate is driven by the 'receipt and redistribution of solar energy
. CO2 in the atmosphere is only 0.001% of the total CO2 held in oceans, rocks and soil.

Earth is a "warm wet volcanic greenhouse,which is recovering from glacial times and is naturally warming".

To reduce modern climate change to one variable - CO2 - is not science.

The slogan ‘stop climate change' is an “advertisement” of some people's ignorance of history, archaeology, astronomy, ocean sciences, atmospheric sciences, as well as geology.

Plimer refers to the SOS coming from the hoaxers and investors in renewables - Save Our Subsidies.

ttbn,

Geologists do contribute to climate science (paleoclimatology), particularly in understanding past climates. Their contribution to our understanding of climate change enables scientists to contextualise the current changes. Climate science is interdisciplinary, involving geology, meteorology, oceanography, and atmospheric sciences.

No one denies that the climate is always changing, nor that there are fluctuations in sea levels or ice sheet sizes, but the current rate of change is unprecedented in the context of human history and is largely driven by human activities, particularly the burning of fossil fuels, which increases atmospheric CO2 levels.

The redistribution of the sun’s energy by the atmosphere and oceans is heavily influenced by greenhouse gases. Greenhouse gases, including CO2, trap heat in the atmosphere, affecting the Earth's energy balance and climate. The atmospheric CO2 may only be 0.001% of the total, but the oceans, rocks, and soil only absorb 50% of what we produce, not 99.998%. The other 50% of what we produce is added to the atmospheric CO2.

Natural cycles suggest that Earth should actually be in a cooling phase now. Even if our planet was recovering from glacial times, however, it would not occur anywhere near as fast as what we’ve seen in recent years.

No scientist reduces climate change to just CO2. Multiple other factors are considered and controlled for, such as solar radiation, aerosols, and land-use changes. But if you’re hearing unqualified activists making this claim, then ignore them. Their opinions are as unreliable as Plimer’s ideologically-driven claims.

Meanwhile in news you most definitely WON'T be reading in your ABC, the Great Barrier Reef is showing record levels of coral coverage...

http://x.com/BjornLomborg/status/1808134536854700215

Yes yes I know. the information is provided by people who are persona non gratia in polite company and therefore will be ignored. On;t approved information is .... ahem....approved.

" but the current rate of change is unprecedented in the context of human history"

Well there's actually no evidence for that although its something that is often claimed and repeated by the climate community. There are lots of places to see this, but the best (or at least my favourite) is Marcott et al 2013 in which the author, in supplementary notes, pointed out that the data resolution for past records, while good over longer spans, isn't precise enough to know whether there were other periods in the recent past where temperatures rose as fast as now. We know as a matter of relative certainty that temperature over longer time spans rose higher than the present but cannot say one way or t'other whether they got there by short sharp 1 degree C/ per century rises or took longer.

Either way, it is very clear that definitive statements like 'its unprecedented' are more in the realm of propaganda than established fact.

Incidentally, Marcoot13 was also the paper, among many others, that showed that current temperatures have been exceeded for at least 3000 of the past 12000 years - ie they aren't even close to unprecedented.

"Natural cycles suggest that Earth should actually be in a cooling phase now."

Another of those things that just get said without actual evidence. No question that it can be argued we are in a cooling cycle, but just as many and valid arguments can be made, based on paleo data that we remain in a warming cycle as the earth recovers from the Little Ice Age.

mhaze,

While it’s true that the resolution of past climate data isn't as fine as modern records, this limitation is controlled for using multiple proxies to smooth out the data. The proxies utilise diverse sources (e.g. tree rings, ice cores), cross-validation, overlap periods, statistical techniques, long-term trends, error bars and uncertainty ranges, and the combining records.

The periods in the Holocene were driven by natural factors, such as changes in solar radiation and volcanic activity. More to the point, they did not occur as rapidly as what we see now, and the extensive range of techniques applied to multiple sources of historical climate data enable us to know this despite the coarseness of it in its raw form.

As for whether the Earth should be cooling, Milankovitch cycles suggest that we should be heading towards a cooling phase over the long term. These cycles, which operate on timescales of tens of thousands of years, have historically been linked to the advance and retreat of ice ages. However, these natural cycles don't operate on the shorter timescales of centuries or decades.

The warming observed since the mid-20th century goes beyond natural recovery from the Little Ice Age (roughly 1300 to 1850). The current rate and magnitude of warming align with the increased greenhouse gas levels caused by human activities, which far exceed the natural variability seen in proxy records.

"More to the point, they did not occur as rapidly as what we see now, "

Well so you keep claiming. But when actual scientists like Marcott do the actual research on those various proxies they see that the resolution of the data isn't fine enough to make definitive claims on scales of one century. Specifically the data resolution, according to Marcott, is only good enough to make assertions of multiple century movements in temperatures. That is we can be reasonably certain about past temperature changes over, say, a 300 year scale but not how the changes occurred within that 300 years. So, for example, we know, or think we know, that there was a significant rise in temperatures in the centuries around 1700BC of up to two degrees. What we don't know and probably never will was whether that was a rapid rise over one century followed by a period of stability at higher temps over several centuries or a slow steady rise over several centuries. And since we can't know that, we can't say with any level of certainity that the current 1 degree/century rise is unprecedented.

" Milankovitch cycles suggest that we should be heading towards a cooling phase over the long term."

Rubbish. Milanovitch looks at climate over periods of multiple 1000s of years. I has nowt to say about cycles within one or two centuries. We know that the recovery leading to the Medieval Warm Period occurred over centuries. There's no reason to think the recover from the Little Ice Age wouldn't also occur of multiple centuries and that we are therefore in a warming phase of a multi-millennial cooling phase

mhaze,

Marcott et al. acknowledged limitations in their data resolution for short-term changes, this does not undermine the broader conclusion that can be drawn from other papers cumulatively. Here's a sample:

Kaufman et al. (2009)
Title: "Recent Warming Reverses Long-Term Arctic Cooling"
Findings: This study focused on the Arctic, using various proxies (lake sediments, tree rings, ice cores) to show a cooling trend over the past 2,000 years that was abruptly reversed in the 20th century due to rapid warming.
http://www.nature.com/articles/ngeo479

Mann et al. (1999)
Title: "Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations"
Findings: This seminal paper, often referred to as the "hockey stick" graph, reconstructed Northern Hemisphere temperatures over the past 1,000 years using multiple proxy records (tree rings, ice cores, sediment cores). It showed a relatively stable climate with a sharp uptick in temperatures in the 20th century, suggesting unprecedented recent warming.
http://www.nature.com/articles/33859

PAGES 2k Consortium (2013)Title: "Continental-scale temperature variability during the past two millennia"
Findings: This study compiled temperature reconstructions from seven continental-scale regions using a wide range of proxy records. It concluded that the late 20th-century warming is unprecedented in more than a millennium for most regions.
http://www.nature.com/articles/ngeo1797

Neukom et al. (2019)
Title: "No evidence for globally coherent warm and cold periods over the preindustrial Common Era"
Findings: By using a large dataset of temperature proxies from around the world, this study found that previous warm and cold periods (like the Medieval Warm Period and Little Ice Age) were not globally synchronous. In contrast, the recent warming is globally coherent and unprecedented in the last 2,000 years.
http://www.nature.com/articles/s41586-019-1401-2

Abram et al. (2016)
Title: "Early onset of industrial-era warming across the oceans and continents"
Findings: This study used coral records, ice cores, and other proxies to show that industrial-era warming began in the mid-19th century and is unprecedented in the context of the past 500 years.
http://www.nature.com/articles/nature19082

(Cont'd)

Schmidt et al. (2012)
Title: "Climate forcing reconstructions for use in PMIP simulations of the Last Millennium (v1.1)"
Findings: This paper provided reconstructions of climate forcings (solar, volcanic, greenhouse gases) over the last millennium, showing that recent forcings from greenhouse gases are unprecedented in both magnitude and rate.
http://cp.copernicus.org/articles/8/1855/2012

Ljungqvist et al. (2012)
Title: "Northern Hemisphere temperature patterns in the last 12 centuries"
Findings: This study used a variety of proxies to reconstruct Northern Hemisphere temperatures, highlighting that the warming of the late 20th century is unprecedented over the last 1,200 years.
http://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL050168

Regarding Milankovitch, you’re right in that they operate over long timescales. According to these cycles, the Earth would be in a long-term cooling phase, gradually heading towards the next ice age. But this natural cooling trend has been overridden by the rapid increase in greenhouse gas emissions from human activities, which have significantly altered the Earth's energy balance and caused recent warming.

The recovery from the Little Ice Age involved a gradual warming trend. However, the rate and magnitude of warming since the mid-20th century far exceed what would be expected from a natural recovery alone. The rapid warming observed over the last century aligns with the sharp increase in greenhouse gas concentrations, which is well-documented and understood as the primary driver of recent climate change. This anthropogenic influence is distinct from the slower, more gradual natural variations seen in earlier periods.

I hope this clarifies things.

John Daysh,

The first link in your post goes to a study that hasn't anything to do with this issue. But I am familiar with the paper you refer to. It doesn't help you case since it is regional only, and talks of a declining trend over 2000 years rather than one century long data resolution.

Mann 2009. Also known as MBH99. Its been so thoroughly debunked as to not be worth discussing. Even the IPCC stopped treating it as valid science.

The third link has nothing to say about single century temperature changes.

Fourth link titled - "No evidence for globally coherent warm and cold periods over the preindustrial Common Era". But there is also no evidence for coherent warming now.

Fifth link is for oceans only AND only for post 1500AD period.

Sixth link doesn't work. But the paper isn't relevant. Showing that forcings are unprecedented says nothing about temperature.

Seventh link goes to a different but irrelevant paper. But the Lindquist paper again only covers the past 500 years.

Again, Milanovitch is about millennial long time scales and has nothing to say about the short periods you refer to. It doesn't preclude warming periods in cooling phases.

" However, the rate and magnitude of warming since the mid-20th century far exceed what would be expected from a natural recovery alone."

These are things that just get said without evidence. For a start mid-20th century showed a cooling even while CO2 levels rose. Equally, the first decade of this century showed no warming even though CO2 levels exploded.

I didn't say the LIA recovery was only natural. I've always agreed that CO2 has played some part. But it ought to be noted that the recovery started long before we started adding CO2 to the atmosphere. You said the current warming is unprecedented in human history. I agree its unprecedented in the last 5 centuries but that's not what you claimed.

The current warming is unprecedented as compared to the past 5 centuries but that doesn't that means anything of significance in terms of proof of the AGW theory.

So why is the Marxist's and Woke and their academic friends pushing the world to address AGW 'anthropogenic global warming' but is not willing to talk to populous nations (in China, India, Africa) about the number of human anthropoids they have and create a policy to reduce them. Maybe they can tell the old that they can't have heating and electricity in temperate countries and see where that gets them. They know who to blame when their houses get cold and their electricity bills triple.

I see this as just another deception to attack the west.

Mhaze,

I’m aware of the myth that does the rounds among denialist circles about the “hockey stick” supposedly having been debunked, but it hasn’t. It did face scrutiny initially, but its main findings have since been vindicated by multiple studies employing different methods and data.

Multiple IPCC assessment reports that continue to use updated versions of the hockey stick graph to illustrate recent temperature trends. Additional studies also confirm the broad pattern observed by Mann et al. (which I’ve listed at the end of my reply).

Regarding Kaufman et al. (2009), this study focused on Arctic cooling and showed that the recent reversal of a long-term cooling trend is exceptional, aligning with broader evidence of unprecedented recent warming.

The PAGES 2k Consortium (2013) shows that the 20th-century warming is unprecedented over the past two millennia across multiple continents, supporting the idea that recent warming is not only regional but also global in nature.

Neukom et al. (2019) indicated that preindustrial warm and cold periods were not globally synchronised, unlike the current period where warming is observed globally, supporting the notion that current warming is unprecedented in its global coherence.

Abram et al. (2016) highlighted that industrial-era warming began in the mid-19th century and is unprecedented over the past 500 years, supporting the broader context of unusual recent warming.

The Schmidt et al. (2012): Here’s a working link http://gmd.copernicus.org/articles/5/185/2012.

Ljungqvist et al. (2012) reconstructed Northern Hemisphere temperatures and supported the finding that recent warming is unprecedented in the past 1,200 years, not 500. (Try this link: http://cp.copernicus.org/articles/8/227/2012)

The regional focus of some studies does not diminish the global implications of rapid recent warming, by the way.

Regarding Milankovitch cycles, these operate over millennia and indicate a long-term cooling trend. The rapid recent warming is inconsistent with these cycles, suggesting that another factor, namely anthropogenic greenhouse gas emissions, is driving current climate change. The mid-20th century cooling was influenced by increased aerosols from industrial activities, which temporarily masked the warming effect of CO2. Once air quality regulations reduced aerosol emissions, the underlying warming trend became more apparent.

(Cont'd)

As for the recent warming pause, short-term variability due to natural factors (like ocean heat uptake) can cause fluctuations in the warming rate. However, the long-term trend over the past century shows clear and significant warming, as confirmed by multiple datasets. Multiple studies indicate that the current rate and magnitude of warming are unprecedented not just in the past 500 years, but in the context of the past several thousand years.

Individual studies may have limitations or specific focuses, the cumulative evidence from a wide array of research supports the conclusion that recent global warming is unprecedented in its rate and magnitude. This conclusion is robustly supported by high-resolution modern data, multiple paleoclimate proxies, and advanced analytical techniques, highlighting the significant role of anthropogenic greenhouse gas emissions in driving recent climate changes. If you have evidence against this, then feel free to share it. I’m not aware of any.

Moberg et al. (2005) used a combination of low- and high-resolution proxies to reconstruct Northern Hemisphere temperatures over the past 2,000 years, supporting the unusual nature of recent warming (http://www.nature.com/articles/nature03265).

Mann et al. (2008) extended the original "hockey stick" reconstruction, incorporating a larger dataset and more advanced statistical methods, reinforcing the conclusion that recent warming is unprecedented over the past two millennia (http://www.pnas.org/content/105/36/13252).

Ljungqvist (2010) used a wide range of proxy data to show significant temperature variability over the past 2,000 years, highlighting the rapid warming of the 20th century as exceptional (http://onlinelibrary.wiley.com/doi/abs/10.1111/j.1468-0459.2010.00399.x).

The PAGES 2k Consortium (2013) compiled temperature reconstructions from seven continental regions, demonstrating that the recent warming is unprecedented over the past 2,000 years (http://www.nature.com/articles/ngeo1797).

Neukom et al. (2019) showed that previous warm and cold periods were not globally synchronous, contrasting with the coherent global warming observed in recent decades (http://www.nature.com/articles/s41586-019-1401-2).

"I’m aware of the myth that does the rounds among denialist circles about the “hockey stick” supposedly having been debunked,"

And there we go. It always reverts to name-calling when the data doesn't support the assertions. Oh, you don't buy the whole AGW theory so you must be a denialist.

You say the hockey stick wasn't debunked yet you yourself are acting like its debunked. The hockey stick's main purpose was to remove the Medieval Warm Period and the Little Ice Age from the record to try to then claim the uniqueness of the 20th century warming. Yet you've acknowledged the MWP and the LIA so you also don't accept the claims of MBH99. I won't bother assailing you with all the evidence advanced by the so many others (but most devastatingly McIntyre and McKitrick) but I'd remind you that after initially lauding MBH99 and using the graph in its reports, the IPCC couldn't drop it quickly enough when the facts came out.

Professor Jones of Oxford University:

"The Hockey Stick is obviously wrong. Everybody knows it is obviously wrong. Climategate 2011 shows that even many of its most outspoken public defenders know it is obviously wrong. And yet it goes on being published and defended year after year."

Again, you claimed it was unprecedented in human history but are unable to show that as a fact. Even if your claims about the last 2000 years were true, (and they're not) that's not human history. In the last 2000 years we've only had three periods of warming, and there's no evidence to show that the current one is any different to the other.

Just going back to something else in the paleo record you previously avoided. Marcott and many others have shown that the current temperatures have been exceeded 25% of the time in the past 12000 years. We continually get told of the dire results of these current high temperatures but somehow we survived the period with higher temperatures - indeed civilisation thrived.

But that gets swept under the carpet because it doesn't suit the narrative. Fear-mongering isn't science.

mhaze,

I didn’t call you any names, nor should I have felt any need to, given the overwhelming body of evidence in support of my claims (some of which I have linked you to). Speaking of which, though, the concept of denialism is legitimate and distinct from scepticism.

The "hockey stick" graph by Mann et al. (1999) did not aim to erase the MWP or the LIA. Its primary goal was to reconstruct past climate variability over the last millennium and to highlight how recent temperature increases compare to historical variations. The graph showed that while there were periods of regional warmth, such as the MWP, these were not as globally synchronised or as rapid as the recent warming observed in the 20th century.

This body of evidence (some of which I have linked to) supports the conclusion that the current warming is not only unprecedented in recent millennia but also poses significant risks due to its rapid rate and global extent, driven primarily by anthropogenic greenhouse gas emissions. Simply, denying that I have provided evidence and repeating unfounded myths about the “hockey stick” is not a rebuttal. You need to explain why the evidence doesn’t support the conclusion.

Once again, numerous studies indicate that the current rate and magnitude of warming are exceptional in the context of the past several thousand years. As just one example, Ljungqvist et al. (2010) reconstructed temperatures for the Northern Hemisphere over the past 2,000 years, highlighting the exceptional nature of recent warming. While the last 2,000 years may not cover the entirety of human history, it includes significant periods of human civilization, providing a relevant context for understanding the impact of recent climate changes (which is what I meant previously by, “in the context of human history”).

Your claim that Marcott et al. (2013) and others have shown that current temperatures have been exceeded 25% of the time in the past 12,000 years and that civilizations thrived during those periods lacks nuance. Marcott et al. (2013) reconstructed global temperatures over the Holocene using a variety of paleoclimate proxies.

(Cont’d)

(Cont’d)

The study found that recent temperatures are indeed comparable to, or slightly higher than, the warmest periods of the Holocene. However, the key difference lies in the rate of change. The current rate of warming is unprecedented within the context of the Holocene epoch.

Warm periods in the Holocene were often driven by gradual changes in Earth's orbit (Milankovitch cycles), solar radiation, and natural CO2 fluctuations. These changes occurred over thousands of years, allowing ecosystems and human societies to adapt gradually. The rapid warming observed in recent decades, driven by anthropogenic greenhouse gas emissions, is occurring at a much faster rate than any natural warming observed in the past 12,000 years.

The claim that temperatures have been exceeded 25% of the time in the past 12,000 years may refer to regional temperature peaks rather than a globally averaged context. Marcott et al. (2013) indicated that while there were warmer periods in specific regions, the global average temperatures and the rate of current warming are unprecedented. One of the crucial aspects highlighted by Marcott et al. is the unprecedented rate of current warming. Even if certain periods had similar peak temperatures, the current rate of temperature increase is much faster, which has significant implications for both natural and human systems.

Human civilizations have thrived during warmer periods in history, but these changes were gradual, allowing societies to adapt over centuries or millennia. The rapid pace of current warming poses a unique challenge. Infrastructure, agriculture, water resources, and ecosystems are being forced to adapt to changes that are happening over decades rather than centuries. The current rapid warming has already led to more frequent and severe weather events, rising sea levels, and shifts in climate zones, which were not experienced during past warm periods. Modern civilization is highly interconnected and dependent on stable climate conditions for food production, water supply, and infrastructure stability. Rapid climate changes threaten these systems in ways that were not a concern for ancient civilizations.

Nothing is being swept under the carpet. Please let me know if there is anything else I have “avoided”.

"The "hockey stick" graph by Mann et al. (1999) did not aim to erase the MWP or the LIA.

Well that's not what was said at the time. Leading up to the MBH99 the climate community had been upset at the way the people they called deniers were using the MWP/LIA to show natural fluctuations in temperatures. Climategate emails show them saying ... “We have to get rid of the Medieval Warm Period.” MBH99 was embraced because it did that.

Mann claims more recent research supports his claims about these periods, but most recent reconstructions reinstate the MWP/LIA.

" As just one example, Ljungqvist et al. (2010) reconstructed temperatures for the Northern Hemisphere over the past 2,000 years, highlighting the exceptional nature of recent warming. "

Well that's not true. First they only looked at extra-tropical NH. They found a Roman Warm Period (RWP), a Dark Ages cool period, a Medieval Warm Period and the LIA. They specifically say the RWP was similar to the most recent temperatures. They specifically say that temperatures in the MWP exceed those currently occurring. They specifically say the temperatures of the MWP were likely higher than any other time in the last 2000 years. They specifically say that the data remains too fragmentary to make claims on decadal levels which was my point all along.

"The study [Marcott13] found that recent temperatures are indeed comparable to, or slightly higher than, the warmest periods of the Holocene. However, the key difference lies in the rate of change. The current rate of warming is unprecedented within the context of the Holocene epoch."

Well that's just wrong. Marcott specifically said that they are higher than 75% of the Holocene ie lower than 25% of the Holocene. (" Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history.")

Whatismore, Marcott specifically said in supplements to the study that the data wasn't good enough to show if the current warming is unprecedented.

/cont

/cont

("Q: Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?

A: Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century.

Elsewhere he says that for most of the period in question the temporal resolution was ~300 years)

No one has been able to answer this question because of the inherent fuzziness in the paleo data. Marcott talks about some of the reasons why the data isn't precise enough to draw conclusions on a decadal scale.

You write: "Marcott et al. (2013) indicated that while there were warmer periods in specific regions, the global average temperatures and the rate of current warming are unprecedented".

Nup he says no such thing. See above.

You keep asserting that the current warming is unprecedented but express it as an article of faith since there is no evidence for it.

The problem for the climate community is that their fear-mongering claims keep getting knocked down, meaning they need to find new things to fret about. Previously we needed to keep temperatures below 2C over 1850 temperatures. Then it was changed to 1.5c. There's no science behind that number. Then when it became clear that even at 1.5c above 1850AD, we wouldn't surpass other warm periods, then they started claiming it wasn't the actual temperature but the rate of change that mattered.

The climate community is always happiest when they can make claims that can neither be proven nor disproven. Another example that all the excess heat is being stored in the deep oceans.

But we've gone past the point where the facts or data matter. Governments simply now proclaim that we need to get to net zero and don't bother themselves with showing why that is the case. The media and a goodly portion of the science community go along for the ride, consequences be damned.

More islands are NOT sinking below the waves, but are actually further OUT of the water, despite what lying S.O.Bs have been telling us to get more money given to them by easy-touches like Albanese Australia.

This time, the Maldives have caught out the confidence tricksters and hysterical climate-bleaters.

mhaze,

The "hockey stick" graph by Mann et al. was intended to reconstruct past climate variability over the last millennium using multiple proxy records, such as tree rings, ice cores, and sediment cores. The goal was to provide a long-term context for recent climate changes, not to erase the MWP or the LIA.

It seems your only evidence to suggest otherwise is to dredge up a long-clarified, out-of-context quote: “We have to get rid of the Medieval Warm Period”. The discussions in the emails were about how to present climate data accurately and ensure that regional phenomena like the MWP were not misrepresented as globally significant in the context of current global warming by addressing known issues with proxy reconstructions.

The discussions among climate scientists were about accurately representing climate data and addressing known issues with proxy reconstructions, not about manipulating data to erase already well-known historical periods. Multiple independent investigations cleared the scientists of any wrongdoing:

UK Parliament Science and Technology Committee Report (2010)
Independent Climate Change Email Review (2010)
US National Science Foundation (2011)
--

What I said regarding Ljungqvist et al. (2010) was indeed true. The study did find that some regional temperatures during the RWP and MWP could have been similar to or higher than modern temperatures, but these were not globally uniform events. The authors noted significant regional variability and acknowledged that the data are too fragmentary to make definitive claims on decadal scales. However, they emphasised that the rapid rate of recent warming is exceptional compared to these past periods.

While the study acknowledged warm periods in the past, it underscored that the current warming trend, particularly in its speed, is unprecedented. This aligns with the broader scientific consensus that recent global warming, driven by human activities, is unique in both its rapid rate and global extent.

(Cont’d)

(Cont’d)

Here are the relevant quotes:

"The results show that the temperatures during the RWP and MWP periods may have been similar to those during the 20th century, but the rapid warming observed in recent decades is exceptional."
"The data indicate that recent warming exceeds the amplitude and rate of the past two millennia, underscoring the impact of anthropogenic factors."
--

You are right about the highest temperatures during, but have missed or misinterpreted the broader context and conclusion of the study, which emphasises the unprecedented nature of recent warming rates. The inability to resolve century-scale changes precisely does not invalidate the study's findings about the exceptional rate of recent warming.

Here are the key points from Marcott et al. (2013)

Current Temperatures:

"Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history." (p. 1198)

The Rate of Change:

"Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century." (p. 1199)

"Despite the limitation, the broader context provided by modern high-resolution data indicates that "Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long-term cooling trend that began ~5000 yr B.P." (p. 1200)

Unprecedented Rate of Warming:

"Climate models project that temperatures are likely to exceed the full distribution of Holocene warmth by 2100 for all versions of the temperature stack." (p. 1200)

The paper emphasises the rapid recent warming compared to the gradual natural variations over the Holocene: "By 2100, global average temperatures will probably be 5 to 12 standard deviations above the Holocene temperature mean for the A1B scenario." (p. 1200)

I hope this clarified everything for you.

ttbn,

I will do as you suggest and read Ian Plimer's new book as soon as I get some time. Thanks.

Geology should definitely be included in true climate science, for example subsidence of some islands due to tectonic plate movement.
Higher Water marks at the shoreline is officially seen as sea level rise, when in reality land at the shoreline had sunk down.

Part of one volcanic island was later seen to have riusen back up slightly at one end but not the other end. So it could be a tilted island. More for geologists to find as fact or not.
But fact remains, relevant sea level has not risen accordingly.

It appears nobody on OLO can answer my question.
Or does climate science claim melted polar ice water does not evaporate?
I ask again.

What percentage of melted polar and glacier ice water evaporates into atmosphere and cloud instead of adding to sea level rise?

JF Aus,

It appears most of the meltwater from polar and glacier ice contributes directly to sea level rise, with only a small fraction evaporating into the atmosphere or becoming part of groundwater systems. Here's a breakdown of what happens to this meltwater:

1. Direct runoff: The majority of meltwater from glaciers and ice sheets flows into the ocean, raising sea levels.

2. Evaporation and sublimation: A small portion of the meltwater evaporates into the atmosphere or sublimates (turns directly from ice to vapour), but this is relatively minor compared to runoff.

3. Groundwater infiltration: Some meltwater seeps into the ground, joining the groundwater system, but this also accounts for a minor part of the total melt.

The following research indicates that more than 90-95% of meltwater ends up in the ocean, with less than 5-10% evaporating or infiltrating the ground. This varies based on regional conditions and climate factors.

The IPCC provides comprehensive assessments of sea level rise and the role of melting ice. Their Fifth Assessment Report (AR5) and Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) offer detailed analyses. (http://www.ipcc.ch/report/ar5/wg1, http://www.ipcc.ch/srocc)

The NSIDC provides extensive data and research on the cryosphere, including glacier melt dynamics and its impact on sea level rise. Their resources frequently cite studies that quantify meltwater contributions. (http://nsidc.org/cryosphere)

The USGS provides information on glacier contributions to sea level rise and the processes involved, including evaporation. (http://www.usgs.gov/faqs/how-would-sea-level-change-if-all-glaciers-melted)

Several peer-reviewed studies provide specific measurements and models of glacier and ice sheet melt, such as:

Bamber, J. L., & Aspinall, W. P. (2013). "An expert judgement assessment of future sea level rise from the ice sheets." Nature Climate Change, 3(4), 424-427. (http://www.nature.com/articles/nclimate1778)

Rignot, E., Velicogna, I., Van Den Broeke, M. R., Monaghan, A., & Lenaerts, J. T. M. (2011). "Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise." Geophysical Research Letters, 38(5). (http://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011GL046583)