Ground Engineering Solutions

Climate Change: The most important chart in the world

  • In these, divided times, unity in Katowice

Our common efforts didn’t consist solely of producing texts or defending national interests. We were conscious of our responsibility to people and commitment for the fate of Earth, which is our home and the home of future generations who will come after us”

An optimistic summing by the President of the 2018 United Nations Climate Change Conference in Katowice (COP24) but also a stark one insofar as there’s no hyperbole here. We are indeed considering the fate of the Earth. Three particular initiatives arose from the summit – a statement of solidarity on the transition to low carbon economies, a commitment to electromobility and a declaration of “Forests for Climate”. Of these the latter is most welcome. As the titular chart below (extracted from the IPCC Special Report “Global Warming of 1.5°C” – normally referred to as SR1.5) shows, we will increase the global temperature by 1.5°C above pre-industrial levels by 2040. To be clear, we will. This can’t be reversed or mitigated – it will happen with high confidence according to the climate modelling. It’s already been exceeded in isolation in 2015. So the provisions of the Paris Climate Agreement and COP24’s implementation outline is a proposal in how with limit and halt further increase on multi-decadal time scales thereafter. Specifically, the models consider sustained net zero global anthropogenic CO2 emissions and declining net non-CO2 radiative forcing. This is hugely ambitious and, as the chart shows, the swing is potentially a full 1°C in global temperature.

But whatever happens in the 20-year time horizon between now and 2040, which will largely be determined by how politicians and world leaders respond to the best advice of climate scientists, we are most likely going to have to deal with a net increase in global temperatures of roughly 0.5°C. We should bear in mind that this is in the context of a commitment by G20 countries to a $60-70 trillion infrastructure expansion proposed by 2030.

What does this mean for civil society? Precipitation deficits inducing droughts; extreme precipitation & higher intensity storms, cyclones, hurricanes & other weather events inducing flooding, landslides and associated geohazards; ice sheet instability & ice sheet loss inducing mean global sea-level rise leading to flooding and ecosystem / habitat loss; all of the foregoing leading to increased health risk, loss of livelihood, food & water supply insecurity, loss of human security & economic growth.

What does this mean for civil engineers? Well, at a fundamental level we will have to recalibrate our design tools. The simplest direct impact of climate change is that a design storm event with a 1 in 200 year return period is no longer that – it’s more like a 1 in 50 year return period. By extension, our basic concepts of design life and design action is no longer valid. How can infrastructural assets be planned, designed and maintained in this environment? There is a fundamental shift in the Gaussian curve – a new normal in Nature.  And therefore, at a conceptual level, we need to recalibrate our mission statements. If Tredgold’s definition of civil engineering  (being the art of directing the great sources of power in Nature for the use and convenience of man) still holds, given its direct reference to the great sources of power in Nature, we must shift as Nature does because our art is only in direction, not in control. It is the latter part of the definition that needs most attention however. No longer can we direct these great sources of power for the use and convenience of man. We must direct these great sources of power for the progression and betterment of mankind and its environment.

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