After hurricane Ophelia hit Ireland last month, I thought I would share a few thoughts that
I've had about climate change, hurricanes and food growing.
I have been trying to learn more about extreme weather events in general, as they can have
such a negative impact on food production throughout the world and in my own gardens.
As part of this, I have been keeping an eye on the development of hurricanes in the North Atlantic.
These extreme weather events are both fascinating
in how they form and develop, and traumatic with the destructive wake that t hey can leave behind.
And with the mindset and experiences of a grower,
I’m looking for signs of climate change having an impact on these systems.
This 2017 season has been a tough one with Harvey, Irma and Maria all becoming seriously
destructive natural disasters. Based on a measurement of its energy throughout
its lifecycle, Irma was the second strongest storm observed in the Atlantic basin since
1950, when more accurate observations from satellites began.
The accumulated cyclone energy of all the storms in the 2017 hurricane season have earned
this year the dubious distinction of being hyperactive.
A lot of this was from the huge storms that made headlines, but it was also due to fact
that 13 storms in a row reached hurricane strength with winds exceeding 120 km/h,
a streak that has not been seen before. But while 2017 has been notable for a number
reasons, it could be argued that all of it is within the scope and range of what has
been observed before and therefore difficult to determine the impact of climate change, if any.
But I felt that Hurricane Ophelia was different, and I wonder if it could be the sign of something new.
This storm began in an area of the middle
of the Atlantic Ocean where not many tropical cyclones form, and those that do start in
this region seem to head west, or stay in the middle of the ocean and eventually stall.
But as this storm strengthened into Hurricane Ophelia it was apparently caught by the meandering
mid altitude jet stream that brought it straight for Ireland.
Ireland does occasionally experience the remnants of hurricanes, but normally after they’ve
circled up along the coast of North America and then make their way eastward to Ireland
as significantly weaker storms. The path that Ophelia took was much more direct,
and on its way it became major category 3 hurricane with maximum sustained windspeed of winds of 185 km/h.
No hurricane of this strength have ever been
seen so far east in this part of the ocean before.
It was probably the worst storm to hit Ireland in 50 years, with sustained winds above 100
km/h experienced along much of the south coast. The entire country was affected, though not
as badly as it could have been as the storm weakened just as it made landfall.
Thankfully there wasn’t too much local damage, and the polytunnels of the RED Gardens survived, barely.
Was this something that is infrequent enough but still within the scope of what could be
expected, or was it an outlier event? Given that so few storms start in this part
of the Atlantic, it is hard to determine how rare any particular behaviour would be.
Are we unlikely to see a storm like this for another 50 years, or are these types of events
going to become much more common? Or does it have the characteristics of something
different at a fundamental level? When a big hurricane hits, we commonly hear
that while we should expect the frequency and intensity of events like this to increase,
we can't be sure that any individual storm was caused by Climate Change.
I've got a big problem with that answer.
In complex adaptive systems like the climate, or an ecosystem, or the soil biology, searching
for that linear path between cause and effect can be misleading.
On the one hand, claiming that this storm was caused by climate change, would be like
me claiming that the great crop of carrots that I grew this year was caused by the really
strong seed that I started with. Yes, the seed produced stronger seedlings
than I’ve seen in the past, and the crop was the best one that I’ve grown, but to
claim that this was cause and effect would neglect the other variables such
as the good weather conditions and my improving skills as a grower.
But, of course the strong seed helped, or, rather I'd feel it would be foolish of me
to claim that the strong seed had minimal or no effect.
I also think it is unhelpful to assume that just because I don’t know the extent
it contributed, I can’t make any claims about the impact of the seed quality.
It seems that this is what we tend to hear about the impact of climate change on hurricanes
and other extreme weather events.
A fascinating factor of hurricanes in the Atlantic is they cannot form until the ocean
surface temperature rises above 26ºC. In other words, there can be a lot of storms
regardless of the temperature of the water, but this particularly destructive type of
storm cannot form or be sustained until the conditions have passed a certain threshold.
I think this idea of a threshold is interesting, and I’ve experienced it very directly in
trying to grow squash and pumpkin in Ireland. While I've always wanted to grow squash it
can be very difficult in the weather conditions here.
A key factor is that squash, like tomatoes, need to ripen to a certain point or they just
aren't the same, they don’t develop the ripe flesh or strong skin for storage.
They need a certain amount of heat and for a certain number of days to grow and ripen
in the gardens, conditions we just don’t get most summers.
Relatively cool weather compounded by the threat of frost, means that it is difficult
and sometimes impossible to produce a ripe squash, even with the fastest and hardiest varieties.
Most seasons, the conditions are below what
I would call the squash threshold. Below this threshold I feel growing squash
is a serious waste of effort and space, but above this threshold an abundant delicious
crop can be grown and stored. What I find interesting is that here in Ireland
it doesn't take much to push the conditions beyond that boundary.
By starting the plants in a hotbox and using fleece to provide the warmer microclimate
for a few weeks after transplanting, I have been much more successful at producing ripe
squash at the end of the season. It seems to only take a few degrees of extra
warmth in the first part of the growing season to bring the microclimate conditions beyond
the squash threshold. For me this is a usefull way at thinking about
what is going on in the gardens, and I wonder what other thresholds there could be out there.
I also wonder if it's possible that the unusual path and strength of Hurricane Ophelia is
not just that of a rare event, but the sign of a threshold being passed?
Are conditions changing so that storms like this can more frequently develop and become
significantly stronger in a part of the ocean where they just haven't been able to exist before.
Could a new weather pattern be emerging, or have I got all of this wrong?
In a few decades Hurricane Ophelia could be seen as the beginning of something that became
much more common, or it could remain a storm that fits within the possibilities that have
existed for many centuries. I suspect that the former is more likely,
and I wonder what to do about that possibility. Storms that we used to expect once every 50
years, or more accurately had a 2% chance of happening in any given year, are possibly
going to become much more frequent. This is what the theory and models of Climate
Change tells us is likely, and what my experiences in the gardens leads me to suspect as well.
But we already get a lot of storms in Ireland, and developing windbreaks and more resilient
infrastructure within and around the gardens is a prudent thing to do.
And to what extent can I really prepare for an extreme and rare event like a hurricane,
beyond perhaps being more aware, and continuing to work to become a better grower.
While I am concious of the need to adapt to a changing climate, including the possibility
of much more extreme storms, I feel that my RED Gardens Project and this YouTube channel
could be part of the process of mitigation. I firmly believe that the more people who
grow food for themselves, the better chance we have of limiting the extent of climate change.
That's a big reasons why I'm doing all of this.
So, thanks for watching. If you like what you see please subscribe,
and if you'd like to support me in this work, please click on this link to my Patreon page.
Any contributions will help me to make more videos like this.