CO2‐warming,rising sea‐level and retreating coasts: review and critique

A CO₂‐warming atmospheric scenario, whereby increased concentrations of ‘greenhouse’ gases result in higher temperatures that either melt near‐polar ice or cause thermal expansion of ocean waters, thus leading to increased sea‐levels and exacerbated coastal erosion, assumes fundamental but unproven cause‐and‐effect relationships. General circulation models have reinforced claims of an accelerated warming and indirectly given support to the complete scenario, but ignore the point that global climate and not just air temperatures have changed over the past century. Indeed, it is difficult to prove that air temperatures have warmed naturally outside of urban centres over this period. To attribute recent temperature increases to anthropogenic factors and to extrapolate these trends to the future also ignores the historic variability of climate. What is more, an eustatic rise in sea‐level cannot be discerned from the background noise of technically or climatically induced changes. Even if sea‐level was rising, coastal erosion may be accounted for better by a suite of inter‐related climatic factors including changes in rainfall regimes, hemispheric circulation and storminess.