Current Climate Concerns - with Rosie Mammatt

Rosie enjoying the morning clouds

Rosie Mammatt - PhD student Rosie has a passion for both weather and sport. She has first hand experience of the impact climate change is having on rowing. Here, she shares some of the details about what’s going on.

What changes are we seeing in the climate in the UK?

Because there are so many weather patterns affecting the UK, it’s hard to say exactly what can be attributed to climate change. But it’s no coincidence that maximum temperature records are being smashed year on year in the UK. We’re also seeing rainfall records topple. 2024 has seen the wettest September on record in Reading, and by the beginning of October we’d surpassed the average annual rainfall amount.  

What about changes in other parts of the world?

Areas of the world like the Middle East, Northern Africa and parts of Australia are rapidly becoming inhospitable to humans. Soaring temperatures and increasing humidity pose danger to life as it prevents the body’s vital organs from working correctly. Reorganisation of large scale weather patterns such as the shifting of storm tracks and reliable rainfall changes leaves more of the most vulnerable communities exposed to the risk of climate change. This ranges from excessive rain which causes flooding, prolonged heat causing drought, or combinations of many factors. Whilst these wider scale pattern changes are still rather uncertain, it is clear that millions of people all over the world are already being affected by climate change, and will continue to be so in the coming decades.

Why are the rivers flooding more often than they used to?

A warmer atmosphere can hold more water vapour, which means that when it rains, it rains more. This means that the equivalent low pressure system or storm forming 100 years ago, for example, would have produced significantly less rain than it would today. Antecedent conditions also play a huge part in the increase in flooding that we have seen. Parched, baked ground absorbs rain very slowly. That is why when you have a thunderstorm after a heatwave, flash flooding occurs because the ground simply cannot absorb rain fast enough. Likewise, waterlogged ground does not have the capacity to absorb more water. That is why in January 2024, we saw rivers up and down the country bursting their banks. We had a prolonged period of excessive rain at the end of 2023, so when the rain continued through January, the water simply had no where else to go.  

We have summer rowing issues too don’t we?

Summer rowing absolutely poses its own challenges. Heatwaves cause river levels to drop. This isn’t often a problem for large rivers like the Thames, but I have vivid memories of having to get out of a boat to drag it over the river bed during a canoe expedition down the River Wye in 2018 - the water barely came above my ankles! Plant growth is also much higher in the summer months which can cause blockages leading to disturbed and reduced flow. 

It also presents challenges for the rowers themselves. Heatstroke is a very real threat when training, but especially during competition. Spending long periods of time on the water, in the hottest hours of the day, usually on exposed areas of a river or lake leaves rowers vulnerable. It’s important during these times to wear sunscreen, drink plenty of water or isotonic and cover up as best you can - a wide brimmed hat and loose long sleeve top are good.  

Is the cleanness of our rivers linked to climate change?

Yes and no. Climate change is adding to and exacerbating a problem we already had in the UK. For decades, rivers in England have been in extremely poor health. Among others, a major culprit for this is the agriculture industry. Fertiliser and manure runoff from fields causes river water to become too nutrient rich. This leads to algal blooms; the rapid growth of algae and plant life in the river, which consequently uses up too much oxygen and starves other aquatic life like fish and amphibians. Climate change will cause this to happen faster, as warmer water and air temperatures speed up this process.

Flooding at the RUBC boathouse

Another issue is stagnant water during times of low river flow. If rivers get blocked with excess plant life, this creates stagnant water. Algal blooms are more likely in stagnant water as there is no through flow to replenish the oxygen levels. It's also an opportunity for pollution to build up to dangerous levels before being washed away. Hotter, drier summers make this situation more likely.

On the other end of the spectrum, very high river levels also cause problems. Sewers fill in times of extreme rainfall, which leads to the use of combined sewer overflows (CSOs) - which is essentially the emptying of raw, untreated sewage into the waterways. With rainfall like we have seen in the last few years, it is becoming an increasingly bigger problem. It has already affected a number of high profile events this year, including the Boat Race and the Paris Olympics.

All of these factors make the river hazardous for aquatic life and for river users. How much longer will it be safe for us to use the river for?

How do you think rowing needs to change to adapt to the changing climate?

It's a tricky one. With the way rowing races work, it requires lots of people travelling to be in one place together, and locations are somewhat limited - there has to be a river or lake big enough. But perhaps there is something that can be done with the timing and location of races. Regatta locations should be chosen with heat stress in mind - there are areas which are less vulnerable to extreme heat. Starting earlier and avoiding the hottest part of the day is safer for the rowers, marshals and race organisers. The season could even be shifted, so that the regatta session isn't in the hottest months of the year.

Gig racing with Rosie and her crew. 

Do you see the changes impacting coastal rowing or beach sprints?

It goes without saying that climate change is having huge impacts on the sea for a number of reasons. Sea level rise from melting ice sheets and thermal expansion of the ocean is leaving more communities vulnerable to coastal flooding. Storm formation also relies on warm sea surface temperatures, and the potential for increased storm activity also brings with it more coastal erosion from high winds and angry seas as these systems make landfall. 

But it's hard to say whether climate change will have the same effect on coastal rowing as it does on river rowing. The summer heat is less likely to be a problem for coastal rowers because of the ocean's cooling influence. The beach sprint season is in the summer and early autumn, as the beach sprinters would risk cold water shock in winter - something which is rarely a problem for river rowers. In winter, when we get the worst of the rain, wind and sea conditions, coastal clubs already have to be cautious to ensure the safety of their rowers. In Pembrokeshire (where I'm from), most coastal rowing clubs retreat inside during the winter months to erg out the worst of the weather. 

Are other sports being affected by climate change?

Absolutely. Grassroots sports such as football and rugby are also being affected massively by waterlogged and flooded playing fields, which leads to cancelled training sessions and matches. All river sports - such as kayaking and canoeing as well as rowing - will be affected by extreme river levels. Outside court sports like hockey and tennis may see matches cancelled due to weather extremes. The impact on individuals is huge - sport and exercise is so important for our physical and mental health. But this will also have a massive impact on clubs. When events and races are cancelled, a major source of income for that club is taken away. Added to the cost of more frequent clean ups - I don't think there was a boat club on the Thames who avoided flooding this year - this will place a significant financial burden on clubs and, in turn, their members.

 Can we do anything about climate change as a sport?

Unfortunately, there's no silver bullet for tackling climate change. But there are things we can do. On a daily basis, reducing the reliance on petrol launches would reduce the carbon footprint of the sport, especially as electric outboard motors become more reliable and available. On the larger scale, we can all think about how often and how far we are travelling, whether that's for races or training camps. Taking the most environmentally friendly options - for example by car sharing or using public transport when possible - reduces the impact of travelling, but this only works up to a certain distance. For longer distance events, I don't think it's as easy as saying "avoid flying", for example, because there'll never be another international competition. It isn't feasible to row across oceans to get to regattas on other continents!