Climate change

IPCC Grand Seminar

I had the great honour to be panellist of the IPCC Grand Seminar arranged today at Lund University by MERGE, BECC and LU Land. I talked about pluvial flooding and how urban areas can be adapted to climate change. With me I bring new ideas on how we can mitigate and adapt to climate change. There are three main points that I want to share from the seminar:

  • The last report from IPCC, the AR6 report on the physical science base of climate change is great. Read it! I think it is great for two reasons: 1) there conclusions are more clear than ever and 2) they have included illustrative figures that very useful in order to explain historic and future climate change, as well as the effects on a wide variety of drivers, like extreme heat, landslides, fire weather, and coastal erosion. With 35 different drivers, there is valuable information independent on your specific interest.
  • The group of climate change deniers is relatively small, about 10% in the U.S. for instance. We should therefore focus on the broad public and use our time to discuss with them.
  • And finally, it is important how we vote in national elections. The elections are one of the most important ways to influence the politics and the system that steers what measures that are taken.
Me at the IPCC Grand Seminar together with skilled researchers, including Markku Rummukainen (Swedish representative in IPCC) and Deliang Chen (one of the authors).

Radical redesign of our cities will lower the flood risk – II of IV, turn the dikes

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Conventional dike in Gretna, Mississippi. Photo: http://commons.wikimedia.org/wiki/User:Infrogmation

Conventional dike in Gretna, Mississippi.
Photo: Infrogmation

Turn flood dikes perpendicular to the coast, so they point at the sea. Stop to fight against the nature and let nature rule your city. This was the radical message when Anuradha Mathur and Dilip da Cunha visited Malmö in March 2014. The new ideas are now discussed among city planners and architects.

There is a saying that ‘there are two kinds of dikes – the ones that did break down and the ones that will break down in the future’. We design dikes with standards that should lower the risk of failure and we choose a safety level for the dike. But, there is always a limit for the construction. One day the dike will break down or water will overtop it during an extreme storm. The clear message from Mathur and da Cunha is that we should stop to fight the nature with dikes.

Their idea is to turn the dikes or levees around and use them for evacuation when a flood comes. On top of the levee buildings could be constructed. Here is a good and safe place for vulnerable buildings, but also for schools. During a flood – because flood will come, these buildings will be used as evacuation centre.

Rising sea water level will flood cities

In the future, we will see higher sea water level due to climate change. Mathur and da Cunha claims that the future sea level rise challenge our understanding of the sea. We need to rethink the urban design fundamentally, as the sea will eat a lot of urban areas along the coast lines. It is not possible to compete with nature.

As the city will be flooded more often with the new turn-around dikes, people will get more aware of the risk and therefore construct the city in a smarter and less risky way. This awareness contributes to flood resilience for the city.

Nature is not like engineering

Sometimes people claim that we should ‘construct natural dikes’. This is an engineering approach to nature, says Mathur and da Cunha. The nature works in systems and not in functions. In Norfolk (USA), where they currently are working with the sea level rise problem, the military base is dominating and the military way of thinking is wide-spread: Conquer the fronts. Conquer the land from east to west. This thinking also transfers to the cities fight against the rising sea. Mathur and da Cunha explained how they work with this idea on conquering and that they could see a shift in people’s idea when they gave workshops about it. In their workshop people would learn how natural systems could be used in an effective way for protection. We should work together with nature and see the sea as a friend, they say. It is time to stop fight against nature.

400 ppm

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I dessa dagar kan man läsa i tidningen att mätningarna vid Mauna Loa nu visar att vi har 400 ppm koldioxid i atmosfären. Det är skrämmande hur mycket koncentrationen stigit på få år. När jag läste till civilingenjör vid Lunds universitet (2003-2008) lärde vi oss att atmosfärens koldioxidkoncentration är 360 ppm. På bara några år har koncentrationen ökat drastiskt, vilket onekligen ger en viss respekt för människans samlade dumhet och avsaknad av framtidsperspektiv. Det är på tiden att klimatfrågan tas på allvar på alla nivåer, från varje enskild individ till stater och internationella maktcentrum. Vi måste sluta subventionera fossil förbränning och börja använda våra resurser med respekt för framtiden.