Origin: Late Middle English, possibly originally from greek "klinein", meaning slope
The weather conditions prevailing in an area in general or over a long period...a region with particular prevailing weather conditions
The climate of the bay throughout history
It's likely that the bay area has been ice-free, vegetated, and capable of supporting grazing animals since at least 14,500 years BP. Evidence of human occupation goes back to the Mesolithic- 12,000 years BP. The bay itself has been infilling with sediment since at least the 18th century, partially due to manmade changes such as the construction of the railway viaduct and the reclamation of the saltmarshes.
Geographr: Karl and Ali CC BY-SA 2.0
Equilibrium
The bay is an extremely dynamic environment, but periodically reaches a state of equilibrium where the inflow and outflow of sediment are relatively equal, the river channels don't move too much, and there isn't a lot of erosion or flooding. Major disturbances have happened in the 19th century, and the 1950s and 60s. Climate changes or mitigation against them could trigger a period of instability.
Wikimedia Commons: Ian Taylor CC BY-SA 2.0
Likely symptoms of climate change
Changing weather patterns
Changing biodiversity
Sea level changes
Sea acidification from dissolved Carbon Dioxide
Temperature rise in the sea and rivers running into the bay
Impact from manmade attempts at mitigation
Heysham Heritage Association http://www.heyshamheritage.org.uk/
Predictions for the North West
Increase in mean winter temperatures of 2.6°C
Increase in mean summer temperatures of 3.7°C
Increase in mean winter precipitation of 16%
Increase in mean summer precipitation of 22%
Less sea level rise than the south due to the effects of isostatic rebound (North) and subsidence (South)
UK-wide increase in severity and incidence of extreme weather events
Flickr: Gidzy CC BY 2.0
Impacts
Of the habitats in the bay area, the coastal limestones, saltmarsh, coastal cliffs, and saline lagoons are judged most at risk of "significant character change" or being destroyed altogether.
Geographr: Karl and Ali CC BY-SA 2.0
Impact on limestones
Increases in biomass due to longer growing season
Invading species outcompeting existing species, and changes in composition of communities
Increased erosion of thin soils in grykes due to more intense rainfall
Change in chemistry of rainfall leading to more erosion of limestone
Less frost damage due to warmer winters
Increased risk of wildfires
Decreased flowering and increased vulnerability to pathogens in heather species
Flickr: Stephen Dawson CC BY-SA 2.0
Impact on coastal habitats
Increased tidal flooding and higher storm surge heights
Acceleration of erosion
Increased sedimentation and barrier breaches causing loss of saline lagoons
Oxidation of sediments and organic matter triggering release of Carbon Dioxide and Methane
Changes in river flows changing the energy and hence sedimentation accretion in the bay
Managed realignment and hard coastal defences resulting in coastal squeeze or total habitat loss
Geographr: Karl and Ali CC BY-SA 2.0
Sea Level Changes
Sea Level changes come from multiple sources: melting of ice sheets, isostatic adjustment, and storm surges
We should also expect decreasing salinity and increased wave height
Projected sea level rise for Edinburgh is 7-54cm by 2095, relative to 1995 levels
Projection for Morecambe Bay is that sea level rise won't be a major issue until 50-100 years time
But ...current defenses, for example the training walls that keep the route to Sunderland Village open, are becoming increasingly ineffective
Geographr: David Long CC BY-SA 2.0
Invasive Sea Species
MCS report record number of sitings of Barrel jellyfish (Rhizostoma octopus), Mauve stingers (Pelagia noctiluca), and Portuguese Man-of-War (Physalia physalia)
Black seabream (Spondyliosoma cantharus), John Dory (Zeus faber) and anchovy (Engraulis encrasicolus) are becoming more common
Leathery sea squirts (Styela clava), wireweed (Sargassum muticum), Orange tipped sea squirt (Corella eumyota), Acorn barnacle (Amphibalanus improvises) all present in increasing numbers in the North-West. All outcompete incumbent species
Andrew Butko via Wikimedia Commons CC BY-SA 3.0
Invasive Land/Freshwater Species
In the rivers: Signal Crayfish (Pacifastacus leniusculus)
On the limestone- Cotoneaster (spp), Buddleia (Buddleja davidii)
On the mudflats- Cord Grass (Spartina anglica)
Geographr: Karl and Ali CC BY-SA 2.0
Manmade impacts
The bay probably reached a stage of dynamic equilibrium in the 1830s and again (after sea defences were added) in the 1950s
As the training walls deteriorate the estuary will return to a more natural meandering regime, with implications for saltmarsh erosion and flood defence stability
Geological features around Walney Island are vulnerable to changes of sediment movement caused by sea defenses
"Holding the line" to defend coastal towns and villages may mean losing low-lying coastal habitats such as sand dunes, saltmarshes, mudflats
However preferred plan predicts net gain of intertidal saltmarsh, sandflats and mudflats around the bay
Geographr: Les Hull CC BY-SA 2.0
How can we mitigate against climate change?
Peat bogs and woodland contribute to carbon sequestration and storage, but if degraded will emit significant amounts back into the atmosphere
Salt marshes regulate many coastal processes such as flooding and erosion
Tree planting along rivers shades water, reducing temperature rises
"Re-alignment" or moving defenses back to higher land because of flood risk may increase opportunities for additional intertidal habitats
Geographr: Gerald Massey CC BY-SA 2.0
Back to the beginning
The climate of the bay is dynamic and has been fluctuating between periods of relative stability, and dramatic change, for millennia, and it's probably heading for another period of change now. Mitigation against some impacts is possible, but may cause additonal problems. The bay must be considered holistically so we can try to minimise the impacts across the board.