The gathering storm
By Dr Judith Wolf
From rising sea level impact on coastal ecosystems to exciting new ways to reduce greenhouse emissions, marine scientist Dr Judith Wolf describes her research into the effect of climate change on the world’s oceans.
Together with colleagues at the National Oceanography Centre (NOC), my team and I are part of the global scientific effort to quantify the real risks of climate change.
A key element of our work is the provision of clear, measured evidence with which policymakers can make informed decisions. For example, the NOC works closely with the Marine Climate Change Impacts Partnership (MCCIP), and is a major contributor to its influential Report Card, which provides policy advisers, decision- makers, ministers, Parliament and the devolved administrations a sharp and succinct update on how climate change is impacting UK coasts and seas.
Deploying an AWAC (Acoustic Waves and Currents) gauge to monitor wave conditions.
The 2020 Report Card makes for sobering reading, and many of its messages are clear and unambiguous: global temperatures are rising and this is leading to warming seas, reduced oxygen, increased acidification and rising sea levels. These global changes are affecting the UK continental shelf and coastal waters, and are having an impact on our ecosystems.
The report also tackles more controversial questions, such as whether extreme events – storms, surges and waves – are getting more severe.
Our models and observations of UK coasts and seas show an average (mean) increase in wave heights in the Northeast Atlantic since the 1950s. However, we have not been able to directly attribute this to climate change – and attributing the cause of individual storms is even harder. Indeed, under a high-emissions scenario, there might even be an overall reduction in mean significant wave height in the North Atlantic by 2100.
With the majority of funding coming from NERC, our work at the NOC has an extremely wide remit – from marine geoscience and modelling to ocean ecosystems, circulation and climate, through the use of cutting-edge technology. Our scientists collaborate nationally and internationally and across disciplines with universities and research institutes. These partnerships are essential. If we are to properly understand how climate change affects the UK we have to look globally.
Climate change and sea defences
Our research into the potential impact of climate change on low-lying coastlines has broken new ground in the use of supercomputers, sensors and other advanced technologies, and our models are in use worldwide.
Regions most vulnerable to a one-metre rise in sea level include East Asia and the Pacific, South Asia, Latin America and the Caribbean, the Middle East and North Africa. We recently studied the likely impacts of climate change-induced sea-level rise, as well as tropical cyclones and changing land use, on the Caribbean island of St Vincent, and in the Pearl River Delta in China.
In St Vincent, we found that a sea-level rise of one metre will place 10% of the main tourist infrastructure at risk. The Pearl River Delta would suffer a similar fate – although with potentially catastrophic human and economic consequences.
So much for the bad effect of global warming on sea level, storms and tides, but how can we harness the power of the sea to our advantage?
In the UK, with additional support from UKRI’s Engineering and Physical Sciences Research Council (EPSRC), we studied whether the power of tidal currents could be harnessed by undersea turbines and converted into renewable energy – without doing irreparable damage to the marine environment. For example, the Pentland Firth in Scotland is the biggest resource of tidal kinetic energy in the UK. We calculated that those tidal streams could provide 10% of the present UK electricity demand, effectively replacing some fossil fuel power stations and providing a predictable energy source.
There is a downside. Our models predict that these turbines would create their own environmental impacts, slowing down the ocean currents and reducing the exchange of water between the ocean bottom and the surface. This could have a negative effect on marine ecosystems.
However, our model also anticipates that global warming would have a similar impact on ocean stratification as the undersea turbines – but it would be ten times more severe.
New advancements in technology will help to mitigate the effects of climate change, but the real difference will come when global policymakers take the bold actions necessary to safeguard the future of our planet.
National Oceanography Centre (NOC)
The National Oceanography Centre is an independent self-governing organisation – a charitable company limited by guarantee. Funded by UK Research and Innovation (UKRI) to work on National Capability programmes, it manages on UKRI’s behalf the National Marine Equipment Pool – Europe’s largest fleet of autonomous and robotic vehicles – as well as two state-of-the-art research ships: RRS Discovery and RRS James Cook.
The centre also provides scientific evidence to support the development of policy, hazard assessment, ocean governance and sustainable development.
Judith Wolf is lead author of the storms and waves section in the 2020 MCCIP Report Card, available online from: mccip.org.ac