You haven’t felt climate change

The following is my review of side project I’ve been working on for my employer.

The human experience is by far the most difficult factor when attempting to relay anthropogenic climate change to a wider audience. Not only are scientists warning that higher emission paths could lead to a climate unfamiliar to anything our species has ever known, but they are also saying that climate has already changed so much that we could argue that we’ve entered a new geological period; the Anthropocene. You would expect that, if they were right, we would already have personally felt it. But you would be wrong.

This conundrum over the human experience is largely exploited by the denial machine and generally forms some of the colloquial discussion within the circles of those who accept the science (ie. “the climate has definitely changed in my region” etc). It’s about the only “truth” the denial machine is able to utilise and distort for their own purposes; “if the climate is changing, why have I feel it?”

The short answer is that it’s hidden in the noise of weather.

Take, for instance, the daily temperature max and min data from one site over the past 55 years, I’ve gone with Adelaide airport, accessed through AustBOM, and you’ll end up with over 40 thousand points and a graph that looks like figure 1. At such a level, there are no obvious trends (except for the diurnal and seasonal trends of course). How could we expect over the 55 years to have personally experienced climate change when you can’t even see it clearly in the data?

Figure 1. Daily temperature max and min. 1950s to 2010.

Even if simplified to monthly max and min values any changes to climate are just as hidden (figure 2).

Figure 2. Monthly temp max and min. 1950s to 2010.

Grabbing two yearly plots or decadal plots 40 years apart (figures 3 and 4 respectively) does little to expose the climate trend either.

Figure 3. Monthly temp max / min for 1956 & 1996
Figure 4. Monthly temp max / min for 1955-1964 & 1995-2004

Working out the temperature anomaly from this data, where the data was run against the 1955 – 1979 averages shows again just how much noise is in the data (figure 5). It’s only when this data is smoothed by 22 months that the warming trend starts to appear (figure 6). Even this, however, is still influenced by other weather patterns, such as the ENSO. The personal experience is not even remotely on such a scale!

Figure 5. 1955-2010 temp anomaly (1955-1979 base)
Figure 5. 1955-2010 temp anomaly, 22 month smoothing (1955-1979 base)

To look at another example – the timing of ecological events – exposes the same situation. Take a theoretical bloom or migration of a bird species which has over the past 60 years, progressed to occur five days earlier than historical expectations. That works out as a shift of 1.37% earlier in the yearly cycle and if at a constant rate of change, roughly 0.02% per year.

Clearly climate change doesn’t occur within the normal human experience and we’re kidding ourselves if we think otherwise. Traditional land use might change, as is sometimes discussed regarding the mass exodus from tribal lands in Africa to large cities over recent years, but how much of the drought is climate change in action and how much would have happened regardless? We can go part way to answer such questions with high certainty, but not always.

This of course does not undermine climate science. Far from it; this should stand as a humbling factor to us outside that field of study. It’s incredibly dynamic and complex. It relies on massive datasets and review of our interpretation of climate (ie. climate models). As someone who spends a lot of time in data analysis, I have a lot of respect for the effort climate scientists go to in researching climate and am glad it’s them, not me, with such a mammoth task at hand.

The human experience lets us down in sensing climate change. It’s far too subtle for our awareness, which should concern us more, not less. Likewise, waiting for the human experience – until a weather event that can only be explained as the result of climate change – is incredibly stupid. To satisfy that suggestion something so far out of our experience would have to occur. It would have to be something more destructive than the flooding and wild fires that occurred across the globe throughout 2010, as the sceptical response made clear – all of that was “normal”. Terrifying to think about…

We haven’t felt climate change and except for if a transitionary state shift occurs, no person will ever feel climate change meaningfully within their life. It’s dangerous to rely on such senses. Returning to my argument from last week, we need to instead stop asking what the future will be, but rather what we would expect the future to look like; plan for goals, not to respond to environmental change, because we’re very likely not to notice change within our experience and undermine our future societies.


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