I have highlighted the key conclusion, that global sea levels fell by between 31 cm and 47 cm between the MWP and LIA.
Although the LIA minimum occurred around 1730 AD, most of the sea level rise since really only began in the late 19thC, or even later as indicated in the tidal gauge records for Brest, one of the longest datasets:
We know that since the late 19thC , sea levels have risen by maybe 25 cm. So Grinsted’s conclusions imply that MWP sea levels were higher than present. HH Lamb came to similar conclusions in the 1970s.
It is worth pointing out that Grinsted’s model is based around two temperature reconstructions:
Moburg et al (2005), which has a pronounced MWP and LIA
Jones & Mann (2004), which has much less MWP/LIA amplitude
The Grinsted paper concludes:
We further find that the Moberg et al. (2005) temperature reconstruction is more consistent with observed sea level rise than the Jones and Mann (2004) reconstruction which we conclude does not have a cold enough Little Ice Age.
The model results are also calibrated against reconstructed sea levels using tidal gauges, (see above graph), giving what the authors describe as “good predictive power”.
Whether the world is 2 to 4 degrees warmer than today by 2100, as the authors suggest, is highly debatable!
But what is apparent is that current sea levels are not unprecedented in recent history. Indeed they point that present sea level is within ~20 cm of the highest level for 110 000 years. This is not in any way alarming, given that most of those 110,000 years spanned the last ice age, and that since then global sea levels have been steadily rising.
In 100 years time, we may get back to MWP sea levels.
“Oddly, while the principal direction suggested by the models is ΔIn[CO₂] → ΔT, the explained variance is impressively low (10-15%) in this direction and impressively high (reaching 90%) in the opposite direction, at ΔT → ΔIn[CO₂].” − Koutsoyiannis et al., 2023
One of the most basic concepts in physics is that causes precede effects and effects follow causes. Determining the directionality sequence is thus essential in any causality analysis.
The assumed CO₂→T causality direction cannot be scientifically supported
The assumption in climate models is that CO₂ causes changes in temperature, or T. More specifically, it is assumed modern global warming has been caused by increases in anthropogenic CO₂ emissions.
“Clearly the results […] suggest a (mono-directional) potentially causal system with T as the cause and [CO₂] as the effect. Hence the common perception that increasing [CO₂] causes increased T can be excluded as it violates the necessary condition for this causality direction.”
A year later these same authors have again conspicuously demonstrated the assumed CO₂→T causality direction cannot be scientifically supported because observations clearly show that variance in T leads or precedes growth rate variance in CO₂ by 6 or more months.
“All evidence resulting from the analyses suggests a unidirectional, potentially causal link with T [temperature] as the cause and [CO₂] as the effect.”
Observational evidence overrules modeled assumptions, regardless of how compelling or mainstream the conventional wisdom.
Cross-correlation analysis reveals CO₂-causes-warming trend alignment depictions are spurious
Because it is widely assumed human CO₂ emissions are the cause and temperature changes are the effect, tendentiously adjusting the axes on graphs to make it appear that the CO₂ and T trends align (i.e., curve-fitting, as shown in the left-side chart below) has become a popular pursuit for those advancing the anthropogenic global warming narrative.
It can be shown, however, that these trend alignments are spurious. Why? Because in the industrial era there have been periods when temperatures have risen rapidly with negligible CO₂ emissions (1700-1750), and decreasing temperatures while CO₂ emissions were rising (1880-1900, 1950-1970). When including all these counter-alignments together and differencing the time series (cross-correlation), the CO₂→T trend alignment disappears. These non-correlations are clearly shown in the right-side charts below. If there are non-correlations, or if the correlations are spurious, causation cannot be established.
Natural CO₂ emissions induced by warming can be shown to be responsible for rising CO₂ concentrations
Fossil fuel emissions amount to 9.4 GtC/year, which is only 4% of the total CO₂ emissions from all sources. In contrast, nature (respiration, freshwater outgassing, fire, volcanism, etc.) produces CO₂ emissions amounting to 216 GtC/year.
It is assumed that the carbon cycle is, in its natural state (without human interference), in perpetual equilibrium, with emissions from natural sources almost perfectly balanced by natural sinks. This presumption is flawed, however, because nature’s sinks don’t decide to only absorb the 216 GtC/year from natural sources as they simultaneously fail to absorb the 9.4 GtC/year from human activities. The 216 GtC/year from nature and 9.4 GtC/year from fossil fuels are instantaneously combined, and nature’s sinks absorb emissions proportionately from the total, ~225 GtC/year.
In their new paper’s appendix, Koutsoyiannis and colleagues have used basic chemistry to show that outgassing from warming and respiration can be biochemically shown to produce emissions rates of 31.6 GtC/year. This is 3.4 times more than the annual emissions from fossil fuels (9.4 GtC/year). Thus, the observation that temperature may potentially a cause of rising CO₂ concentrations appears to be observationally supportable. A substantial portion of modern CO₂ rise may thus be natural.
Natural mechanisms for warming may include the natural increase in sunshine duration
If rising CO₂ concentrations cannot explain modern warming due to the violation of the requisite causality direction, what can?
As has been detailed extensively in many other observational studies, the recent decline in Earth’s planetary albedo (clouds, aerosols) has been reflecting less solar radiation and increasing sunshine duration in recent decades. This, in turn, warms the surface.
A 0.01 change in planetary albedo can induce a radiative forcing of ±3.4 W/m² (Wielicki et al., 2005).
Koutsoyiannis and colleagues cite CERES data that depict a falling linear trend of -0.0019 per decade in planetary albedo since 2000. This can be shown to have elicited a +1.4 W/m² positive imbalance from incoming shortwave, which is sufficient to explain the modern radiative forcing associated with rising temperatures.
So the warming in recent decades may be natural. The CO₂ increases resulting from the natural warming may be substantially natural too. And these results are observationally supportable.
Given the evidence presented in this new study, the claim that human CO₂ emissions are the cause of modern warming is not observationally supportable.
New studies find recent non-warming and/or a warmer Medieval Warm Period.
From 1785-2015 (231 years), the warmest 21-year period in India’s Himalayan region occurred from 1890-1910 (Rastogi et al., 2023). The years spanning 1995-2015 were the 4th warmest and 1946-1966 was the 2nd warmest period.
Over the last 1000 years along Eurasia’s extensive Silk Road trade routes, the Medieval Warm Period (MWP) was warmer than the Current Warm Period (CWP), as “the amplitude of the warming during the CWP did not exceed that during the MWP” (Chen et al., 2023).
Temperatures in northeastern Asia are no warmer today than the 1800s or 1940s (Du et al., 2023). The warmest period in the Common Era occurred during Medieval times (830-850 CE).
In the last 170 years, 8 of the 10 coldest years occurred between 1965-2012.
A new study finds reconstructed temperatures in Iran align well with the “actual” temperatures for recent decades (1976-2014). And when the reconstructed temperature record is extended to 1657, the long-term trend shows no net warming trend in the last 357 years.
Global warming, climate change, all these things are just a dream come true for politicians. I deal with evidence and not with frightening computer models because the seeker after truth does not put his faith in any consensus. The road to the truth is long and hard, but this is the road we must follow. People who describe the unprecedented comfort and ease of modern life as a climate disaster, in my opinion have no idea what a real problem is.
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners. View more
Cookies settings
Accept
Privacy & Cookie policy
Privacy & Cookies policy
Cookies list
Cookie name
Active
Wer wir sind
Textvorschlag: Die Adresse unserer Website ist: https://climate-science.press.
Kommentare
Textvorschlag: Wenn Besucher Kommentare auf der Website schreiben, sammeln wir die Daten, die im Kommentar-Formular angezeigt werden, außerdem die IP-Adresse des Besuchers und den User-Agent-String (damit wird der Browser identifiziert), um die Erkennung von Spam zu unterstützen.
Aus deiner E-Mail-Adresse kann eine anonymisierte Zeichenfolge erstellt (auch Hash genannt) und dem Gravatar-Dienst übergeben werden, um zu prüfen, ob du diesen benutzt. Die Datenschutzerklärung des Gravatar-Dienstes findest du hier: https://automattic.com/privacy/. Nachdem dein Kommentar freigegeben wurde, ist dein Profilbild öffentlich im Kontext deines Kommentars sichtbar.
Medien
Textvorschlag: Wenn du ein registrierter Benutzer bist und Fotos auf diese Website lädst, solltest du vermeiden, Fotos mit einem EXIF-GPS-Standort hochzuladen. Besucher dieser Website könnten Fotos, die auf dieser Website gespeichert sind, herunterladen und deren Standort-Informationen extrahieren.
Cookies
Textvorschlag: Wenn du einen Kommentar auf unserer Website schreibst, kann das eine Einwilligung sein, deinen Namen, E-Mail-Adresse und Website in Cookies zu speichern. Dies ist eine Komfortfunktion, damit du nicht, wenn du einen weiteren Kommentar schreibst, all diese Daten erneut eingeben musst. Diese Cookies werden ein Jahr lang gespeichert.
Falls du ein Konto hast und dich auf dieser Website anmeldest, werden wir ein temporäres Cookie setzen, um festzustellen, ob dein Browser Cookies akzeptiert. Dieses Cookie enthält keine personenbezogenen Daten und wird verworfen, wenn du deinen Browser schließt.
Wenn du dich anmeldest, werden wir einige Cookies einrichten, um deine Anmeldeinformationen und Anzeigeoptionen zu speichern. Anmelde-Cookies verfallen nach zwei Tagen und Cookies für die Anzeigeoptionen nach einem Jahr. Falls du bei der Anmeldung „Angemeldet bleiben“ auswählst, wird deine Anmeldung zwei Wochen lang aufrechterhalten. Mit der Abmeldung aus deinem Konto werden die Anmelde-Cookies gelöscht.
Wenn du einen Artikel bearbeitest oder veröffentlichst, wird ein zusätzlicher Cookie in deinem Browser gespeichert. Dieser Cookie enthält keine personenbezogenen Daten und verweist nur auf die Beitrags-ID des Artikels, den du gerade bearbeitet hast. Der Cookie verfällt nach einem Tag.
Eingebettete Inhalte von anderen Websites
Textvorschlag: Beiträge auf dieser Website können eingebettete Inhalte beinhalten (z. B. Videos, Bilder, Beiträge etc.). Eingebettete Inhalte von anderen Websites verhalten sich exakt so, als ob der Besucher die andere Website besucht hätte.
Diese Websites können Daten über dich sammeln, Cookies benutzen, zusätzliche Tracking-Dienste von Dritten einbetten und deine Interaktion mit diesem eingebetteten Inhalt aufzeichnen, inklusive deiner Interaktion mit dem eingebetteten Inhalt, falls du ein Konto hast und auf dieser Website angemeldet bist.
Mit wem wir deine Daten teilen
Textvorschlag: Wenn du eine Zurücksetzung des Passworts beantragst, wird deine IP-Adresse in der E-Mail zur Zurücksetzung enthalten sein.
Wie lange wir deine Daten speichern
Textvorschlag: Wenn du einen Kommentar schreibst, wird dieser inklusive Metadaten zeitlich unbegrenzt gespeichert. Auf diese Art können wir Folgekommentare automatisch erkennen und freigeben, anstatt sie in einer Moderations-Warteschlange festzuhalten.
Für Benutzer, die sich auf unserer Website registrieren, speichern wir zusätzlich die persönlichen Informationen, die sie in ihren Benutzerprofilen angeben. Alle Benutzer können jederzeit ihre persönlichen Informationen einsehen, verändern oder löschen (der Benutzername kann nicht verändert werden). Administratoren der Website können diese Informationen ebenfalls einsehen und verändern.
Welche Rechte du an deinen Daten hast
Textvorschlag: Wenn du ein Konto auf dieser Website besitzt oder Kommentare geschrieben hast, kannst du einen Export deiner personenbezogenen Daten bei uns anfordern, inklusive aller Daten, die du uns mitgeteilt hast. Darüber hinaus kannst du die Löschung aller personenbezogenen Daten, die wir von dir gespeichert haben, anfordern. Dies umfasst nicht die Daten, die wir aufgrund administrativer, rechtlicher oder sicherheitsrelevanter Notwendigkeiten aufbewahren müssen.
Wohin deine Daten gesendet werden
Textvorschlag: Besucher-Kommentare könnten von einem automatisierten Dienst zur Spam-Erkennung untersucht werden.