<
https://theconversation.com/sea-levels-around-africa-are-rising-faster-than-the-global-average-whats-behind-this-alarming-trend-276888>
"For over three decades, satellites orbiting Earth have measured the height of
the ocean surface with remarkable precision. These measurements are crucial
because changes in ocean height are one of the clearest indicators of how our
planet is responding to climate change. Rising ocean surfaces signal warming
temperatures, melting ice and shifting ocean currents.
These all directly affect coastal communities through flooding, erosion and
habitat loss. Even a small rise in the baseline sea level means that normal
tidal cycles and storm surges reach further inland. This can turn high tides
into damaging flood events.
Many people assume ocean levels are uniform, like water sitting flat in a
bathtub. In reality, the ocean surface is surprisingly uneven. Winds push water
in certain directions. Ocean currents redistribute heat. Temperature
differences cause water to expand or contract. Even variations in Earth’s
gravity field create bumps and dips in the sea surface. All these factors
combine so that sea level can vary by tens of centimetres from one region to
another.
When we say sea level has risen, we’re comparing it to a stable reference
level, the distance between the satellite and the ocean surface.
I’m an oceanographer and geophysicist who specialises in these measurements. My
research team and I analysed ocean height measurements collected by radar
instruments on orbiting satellites from 1993 to 2024, for all waters
surrounding Africa.
Our analysis revealed that African seas have risen by approximately 11.26cm
since 1993. This process is driven by warming waters and melting ice.
African sea levels are rising by approximately 3.54 millimetres each year,
which exceeds the global average of 3.45 mm/yr. Perhaps more troubling is that
the pace of rise is speeding up, especially in African waters. This
acceleration is a long-term trend driven by ongoing ocean warming and ice sheet
melting, and it persists regardless of whether any individual year features an
El Niño or a La Niña. The ocean continues to absorb heat and receive meltwater
from ice sheets year after year, and it is this relentless accumulation, not
any single climate cycle, that drives the long-term acceleration.
Africa’s 38 coastal nations are home to over 200 million people living near the
shore. Rising seas threaten these communities with flooding, coastal erosion,
and saltwater contamination of drinking water and farmland. Rising and warming
seas also disrupt fisheries that millions of Africans depend upon for food and
livelihoods."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
