Palm Trees Growing in Ireland

The climate is mild enough in North West Ireland for palm trees to grow because of the Atlantic meridional overturning circulation which transports heat from the Southern Hemisphere and the tropics to the North Atlantic. The photo below is being used as an illustration in a publication of the U.S. Geological Survey on the subject of rapid climate change. It is included as figure 1.7 (with permission) in chapter one (SAP 3.4.1) written by Peter Clark, Andrew Weaver, Ed Brook, Edward Cook, Tom Delworth, and Konrad Steffen. The photo was made on January 15, 2004 at Mullaghmore Head in County Sligo, Ireland.

The final version of the paper on climate change is online now at .

Next photo of Mullaghmore Head. Previous photo of Mullaghmore Head.

Palm Trees on Mullaghmore Head, Sligo, Ireland. A group of about 9 or 10 palm trees are growing behind a stone wall at a bend of the road next to the Atlantic Ocean. The mountains of County Donegal are barely visible on the horizon.

A paper from 2018 describes the mechanism and the possibility of the transfer warmth to Ireland coming to an end. Mechanisms Governing the Development of the North Atlantic Warming Hole in the CESM-LE Future Climate Simulations Melissa Gervais Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, Pennsylvania, and Lamont-Doherty Earth Observatory, Columbia University, New York, New York

A warming deficit in North Atlantic sea surface temperatures is a striking feature in global climate model future projections. This North Atlantic warming hole has been related to a slowing of the Atlantic meridional overturning circulation (AMOC); however, the detailed mechanisms involved in its generation remain an open question. An analysis of the Community Earth System Model Large Ensemble simulations is conducted to obtain further insight into the development of the warming hole and its relationship to the AMOC. It is shown that increasing freshwater fluxes through the Arctic gates lead to surface freshening and reduced Labrador Sea deep convection, which in turn act to cool Labrador Sea sea surface temperatures. Furthermore, the resulting changes in surface ocean circulation lead to enhanced transport of cooled Labrador Sea surface waters into the interior of the subpolar gyre and a more zonal orientation of the North Atlantic Current. As a result, there is an increase in ocean advective heat flux divergence within the center of the subpolar gyre, causing this warming deficit in North Atlantic sea surface temperatures. These local changes to the ocean circulation affect the AMOC and lead to its slowdown.

A more recent paper concerning the Atlantic meridonal overturning circulation is at One of the authors had a copy of the full paper on a web page at at the time of this writing.

Episodic iceberg-discharge events from the Hudson Strait Ice Stream (HSIS) of the Laurentide Ice Sheet, referred to as Heinrich events, are commonly attributed to internal ice-sheet instabilities, but their systematic occurrence at the culmination of a large reduction in the Atlantic meridional overturning circulation (AMOC) indicates a climate control. We report Mg/Ca data on benthic foraminifera from an intermediate-depth site in the northwest Atlantic and results from a climate-model simulation that reveal basin-wide subsurface warming at the same time as large reductions in the AMOC, with temperature increasing by approximately 2#°C over a 1-2 kyr interval prior to a Heinrich event. In simulations with an ocean model coupled to a thermodynamically active ice shelf, the increase in subsurface temperature increases basal melt rate under an ice shelf fronting the HSIS by a factor of approximately 6. By analogy with recent observations in Antarctica, the resulting ice-shelf loss and attendant HSIS acceleration would produce a Heinrich event.
doi: 10.1073/pnas.1104772108

We also have photos of Ireland from April and May 2007 and photos of Ireland from July 2005 and more photos of Ireland from January 2004 .

An interesting paper on the Atlantic meridonal overturning circulation:

Physical Sciences - Environmental Sciences:
    * Matthias Hofmann
    * and Stefan Rahmstorf
Tipping Elements in Earth Systems Special Feature: On the stability of the 
Atlantic meridional overturning circulation
PNAS published online before print November 6, 2009, 
PDF copy of the paper on the stability of the Atlantic meridonal overturning circulation is at

Another paper published in 2018: 12 APRIL 2018 | VOL 556 | NATURE | 191

The Atlantic meridional overturning circulation (AMOC)—a system of ocean currents in the North Atlantic—has a major impact on climate, yet its evolution during the industrial era is poorly known owing to a lack of direct current measurements. Here we provide evidence for a weakening of the AMOC by about 3 ± 1 sverdrups (around 15 per cent) since the mid-twentieth century. This weakening is revealed by a characteristic spatial and seasonal sea-surface temperature ‘fingerprint’—consisting of a pattern of cooling in the subpolar Atlantic Ocean and warming in the Gulf Stream region—and is calibrated through an ensemble of model simulations from the CMIP5 project. We find this fingerprint both in a high-resolution climate model in response to increasing atmospheric carbon dioxide concentrations, and in the temperature trends observed since the late nineteenth century. The pattern can be explained by a slowdown in the AMOC and reduced northward heat transport, as well as an associated northward shift of the Gulf Stream. Comparisons with recent direct measurements from the RAPID project and several other studies provide a consistent depiction of record-low AMOC values in recent years.

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Palm Trees Growing in Ireland