x Abu Dhabi, UAEWednesday 26 July 2017

Doha climate talks are over - now to pick up the pieces

With no true political consensus, it will be left to the world's engineers and meteorologists to prepare for the fallout of climate change.

The UN Climate Change Conference in Doha, which concluded on Saturday, was a mixed bag of success and failure. It saw agreement to a second commitment period of the Kyoto Protocol from 2013 to 2020. However, at present, this will only cover Europe and Australia, which produce less than 15 per cent of the world's greenhouse gas emissions.

And while there was commitment, in principle, from developed nations to compensate developing nations for the impacts of climate change, only modest progress was made on the ambition of forging, by 2015, a new post 2020 global climate deal.

Given the lofty rhetoric, and the surge in recent dangerous weather attributable to changes in climate, the world expected more.

One of the most impassioned speeches at the summit was by UN Secretary-General Ban Ki-moon. He asserted climate change is an "existential challenge for the whole human race - our way of life, our plans for the future" and particularly highlighted problems resulting from "abnormal [weather] which is now the normal".

One example cited by the UN Secretary-General was the flooding in New York City in November. The devastation wrought by super-storm Sandy - 253 deaths, and over $50 billion (Dh183.5 billion) in economic damage and disruption - is inevitably raising fresh concern about climate change.

One key question post-Sandy is whether climate change means storms will be more intense. The odds are that they will, with the biggest threat from increased flooding caused by sea-level rises as well as increases in rainfall. This has key implications for all of us, especially governments and insurers, as they assess and plan for volatile weather.

The World Meteorological Organisation, which is part of the United Nations, has a committee (of which Professor Chan is a member) that looks at the relationship between climate change and tropical cyclones. It has noted that projections indicate that global warming will cause globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of up to 11 per cent by 2100. Increases in the order of 20 per cent in rainfall rates within 100 kilometres of the storm centre are also projected.

As occurred with Sandy, a crucial issue is that rainfall will likely increase when cyclones hit land. Studies have found that the frequency of heavy rain events, as well as the rainfall intensity, has increased. This has led to a higher occurrence of severe flooding.

Incidences of flooding are likely to increase due to global warming because of increased moisture in the atmosphere. Moreover, because of sea-level rises caused by global warming, flooding due to storm surges associated with cyclones will exacerbate.

The sea level rise factor is especially important because coastal communities have grown sharply in recent decades. In the case of Sandy, most damage was caused by flooding, with the exception of weak structures near the shoreline destroyed by strong winds.

As the Sandy episode revealed, there have been tremendous advances in our understanding of the physics that drive cyclones. Computer forecasting now does a great job in predicting areas where a cyclone will likely hit.

However, there has been much less success in predicting the maximum winds of cyclones. Moreover, little attention has been paid to forecasts of cyclone sizes (horizontal extent of damaging winds, for instance). Such predictions are important for issuing wind and storm surge warnings.

Forecasting models also have considerable difficulty predicting amounts of rain that can fall in particular locations. In many cases, unanticipated copious amounts of rain have led to disastrous consequences.

Based on the very best scientific assessments about storms of the future, insurance companies should intensify their focus on evaluation of flood risks of any asset to be insured, given their huge stake in any losses. Meanwhile, government disaster-preparedness agencies must urgently re-evaluate flood-mitigation plans.

As in the Netherlands, where Delft University has led much ground-breaking work, this should include assessment of dykes and sea walls as the first line of defence against storm surges; drainage systems within cities, not only for roadsides but for subways and tunnels; reinforcement of dangerous slopes; and establishment of warning systems for flash flooding in mountainous regions.

Moreover, increased public sector support is needed for research to improve weather monitoring systems and computer forecasting.

In addition, because significant numbers of high rise buildings are being built in coastal cities that are subject to cyclones, more research is needed about high rise turbulence (instrument towers have been constructed on China's south coast to measure this). Such data will enable engineers to improve safety of such structures, while providing invaluable insight on the energy transfer of the ocean to cyclone winds.

Climate talks in Doha are over, with few concrete gains in addressing climate change. It is now up to the world's engineers and meteorologists to prepare for the fallout.

 

Lord Hunt is visiting professor at Delft University and former Director-General of the UK Meteorological Office. Johnny Chan is chair professor at City University of Hong Kong, and Chair of the World Meteorological Organisation's Tropical Cyclone Panel