Saving our Skins: Chapter 21. A Safer World?
Saving our Skins: Chapter 21. A Safer World?
Atmospheric Reflections from a Lauder Stargazer
The continuing story of “Saving our Skins”. Our skins may be saved, but our bacon may be cooked ...
Updated September 5, 2021.
A picture’s worth a thousand words. In 2018, when I produced the first version of the graph shown below, I at last started to feel that I might finally be able to retire, confident in the knowledge that the last 4 decades of my life’s work at Lauder had been worthwhile. The ozone problem seemed to be on the mend, and UV levels were no longer increasing, at least at Lauder. As you may recall from Chapter 15, that was the necessary (but not sufficient - I hasten to add) condition I’d imposed on my retirement in discussions with Greg Bodeker two decades earlier.
The graph demonstrates the huge success of the Montreal Protocol in curbing UV increases at Lauder. Without it, in the World Avoided, the UVI would have continued to ramp upwards inexorably. But the reality is quite different. There seems to be little reason for concern now about increased UV in response to ozone depletion at Lauder. In fact, during these summer months, when UV is most intense, there seems to have been a decrease in the last few years. Our previously reported increase in UV due to ozone depletion in the 1990s can be seen clearly in the figure, where it’s also apparent that it failed to continue in the following years. But whether the UV would continue to remain stable or decline again in the future, and what was happening elsewhere, remained to be seen.
We at Lauder were a small part of that success in reining in further increases in UV radiation due to ozone depletion. Hopefully our actions will save some lives in the future. Perhaps they already have. From the success of the Montreal Protocol, a 20 percent decrease in ozone and more than a 20 percent increase in sun-burning UV has already been avoided. Early UNEP Environmental Assessments of Ozone Depletion predicted that, if all other factors remain unchanged, skin cancer rates would increase by 3 percent for every 1 percent reduction in ozone. So, without the success of the Montreal Protocol, we would already be consigned to future rates of skin cancer more than 50 percent higher than at present (allowing for a latency period between exposure and diagnosis). In addition to our contributions to the science of ozone depletion, we at Lauder have also educated the public about the risks of UV damage, and have provided tools to help avoid overexposure. They may be our greatest gifts. There’s no excuse now for people to not understand the risks. They are avoidable. It may be too late for baby-boomers like me, who are now suffering the consequences of overexposure to UV in our youth before the risks were appreciated. For years I’ve had solar keratoses removed from my hands and face by liquid nitrogen freezing.
Those keratoses are the legacy of hours spent as an agricultural contractor in my youth, working outdoors through the summers without adequate protection. I recently completed a 3-week course of twice-daily full-face applications of Efudix™, a cream that’s used to treat precancerous and cancerous growths in the skin caused by exposure to sunlight. It wasn’t a pretty sight at the time (see the photo in chapter 11). The sun-damaged areas - in my case most of my face - erupted into sores. But they eventually peeled off to reveal revitalised skin below, and the scars healed over the next few days. So, it’s all good now. The treatment was needed to ensure that the skin damage already there didn’t go on to develop into full-blown skin cancer.
My continuing outdoor lifestyle in sunny Alexandra doesn’t help, but at least I know now to apply sunscreen each day. I do this by applying an after-shave sun-protective moisturiser each morning. The product I use has a sun protection factor (SPF) of 15, which is lower than ideal, so I supplement it with a higher-SPF sunscreen if I’m going outdoors in the sun for extended periods. I also know to cover up as much as possible, and to seek protection from sunlight, especially around the periods of highest sun. By avoiding sun exposure for 1.5 hours either side of local noon, the risk is halved. Remember though that in most of New Zealand, solar noon in summer occurs closer to 1:30 pm than 12:00 noon; so, the danger period is from 12:00 noon to 3:00 pm (rather than 10:30 am to 1:30 pm). And any extension to that avoidance period is also highly beneficial. Those benefits are clearly seen in our smartphone apps (e.g., GlobalUV, uv2Day, or UVNZ) that include tailored behavioural advice for UV exposure.
Aside from our skin-damage, we baby boomers have been the lucky generation. Especially if we were fortunate enough to have been born in a country like New Zealand. I fervently hope that the world will wake up and take heed of the climate risk in time, so my children, grandchildren, and future generations will be able to live in a similarly unspoilt world. The Kigali amendment (mentioned in chapter 17) to the Montreal Protocol, and the emergence of renewable energy to replace fossil fuels, give cause for hope. But will it happen in time? Europe is doing its bit. So too the USA, despite the obstructive efforts of their current aberrant president. But the key will be the new world leaders: India and China. As Britain and USA dominated the 19th and 20th centuries, those Asian countries are already the new game-in-town for the 21st century.
Fossil fuel use continues to increase rapidly despite all the talk. Depressingly, even as the problem has become better understood and more pressing, the rate of use of fossil fuels has continued to accelerate. Our use of them since 1990 already exceeds our total use prior to that time. Or, as Barry Saxifrage put in Canada’s National Observer on July 31 2019: half of mankind’s total fossil fuel burn has occurred in just the last 30 years!
In the past it had been argued that because the developed western world was responsible for most of the historical emissions of CO2, they should bear the brunt of costs of moving to a carbon free economy. With half the fossil use since 1990 that argument is less persuasive, but I still think China - and perhaps other Asian countries like India and Korea - deserve a break. Although they’ve become the factory for the entire world, there wouldn’t be any emissions if there weren’t consumers. The consumers are to blame. And that’s still the developed western world, as we’ve just been reminded with the halt in supply of so many products as a result of the present coronavirus (Covid-19) outbreak. As well as reducing consumption, we need to diversify the production.
Compared with our success in curbing ozone depletion, progress in curbing greenhouse gas emissions – admittedly a much more difficult problem – is dismal. In about the same period of time it took to discover and turn around the ozone problem, the threat to climate has doubled. We’ll have to do a lot better in the next 30 years if we’re to avoid crossing critical “tipping points” - points of no return, where changes become entrenched and impossible to reverse.
We passed a critical tipping point for ozone in the late 1970s, when the concentration of atmospheric chlorine became large enough for the Antarctic ozone hole to form. Without the Montreal Protocol there would have been no return, and despite the heroic efforts of so many the ozone hole is still expected to recur each spring for most of the 21st century. In that case, a reversal was possible.
For climate change the effects will be worse and recovery times from tipping points will be much longer. For example, with increasing temperatures, mountain ranges like the Himalayas will eventually lose their glaciers, which currently act as reservoirs that store water for slower release over the summer months. At a population level, conflicts will arise from that tipping point.
Take the fate of Bangladesh. The livelihoods of tens of millions living there on the Ganges river delta will be slowly inundated from rising sea level. By the 2080s, sea levels are expected to have increased 65 cm, which will result in 40 percent of productive land being lost in Southern Bangladesh. About 20 million people in the coastal areas of Bangladesh are already affected by salinity in their drinking water. Rising sea levels and more intense cyclones and storm surges will intensify the contamination of groundwater and surface water causing more outbreaks of diseases like diarrhoea.
At the same time there won’t be enough fresh water from Himalayan rivers like the Ganges, because permanent glaciation will be a thing of the past. The water will flow straight off the mountains whenever it rains, or whenever the snow melts, rather than being locked up in glaciers. Some will be trapped by dams in India before it reaches Bangladesh. The Bangladeshis won’t have enough fresh water and they won’t have an escape route, because that is blocked by their mortal enemy, India. Another monumental disaster caused when Britain carved up its Empire. This is just one of many examples of potential conflict outlined in Gwynne Dyer’s Climate Wars, which I highly recommend.
The key to long-term change is the oceans. As for air temperatures, sea-surface temperatures have increased by about 1°C since the beginning of the 20th century – with an accelerating rate of increase in recent years. But it’s the amount of extra heat energy they now store that’s most relevant, and most astounding. Over the last 20 years, thousands of drifting buoys have been deployed to monitor ocean temperatures from the surface down to depths 2,000 m and more. Data from these buoys clearly show the effects of increasing greenhouse gases which trap outgoing radiation in the Earth’s atmosphere, so the incoming energy from sunlight is no longer being balanced by the outgoing infrared energy.
Whereas the mean incoming energy at the Earth’s surface is about 160 Watts per square meter, the outgoing energy is smaller by about 0.6 Watts per square metre. That difference doesn’t sound much, until you realise just how many square meters there are on the Earth’s surface. The energy imbalance caused by the build-up of greenhouse gases in the atmosphere is equivalent to the energy emitted by the continuous detonation of 5 Hiroshima bombs every second[1]. Most of the excess energy (more than 70 percent) ends up being deposited in the ocean, and analysis of temperature data from these drifting buoys shows that the increases in oceanic heat energy are entirely consistent with calculated projections.
To me that was a watershed finding for climate change, comparable with the “smoking gun” for ozone depletion mentioned earlier (near the end of chapter 10). The increased oceanic heat energy represents an average over a huge volume of water, without complications of seasonal or diurnal temperature changes, weather effects, or growing urban “heat islands”. The oceans are also by far the largest sink of CO2 in the world, with 93 percent of the world’s CO2 being trapped in its vegetation and coral. The oceans have already mitigated climate change in two ways. Firstly, they have absorbed much of the excess CO2 emitted from the burning of fossil fuels, though that rate now seems to be slowing. Secondly, because of the high specific heat of water compared with air, oceans have absorbed much of the thermal energy in the atmosphere.
Ice-melt is a major tipping point for climate change. If too much ice melts then the planetary albedo (i.e., reflectance) becomes smaller, so less energy is reflected and more absorbed, irreversibly accelerating climate change. Changes in ice cover have large effects on UV exposure too. When ice sheets melt, the organisms that lived under them are exposed to much higher levels of UV radiation, while those above the surface are exposed to much lower levels. Changes in climate can also affect cloud cover, which can potentially have large effects on the transmission of UV radiation to the surface.
Now that ozone seems to be under control, future changes in UV will be dominated by changes in clouds and aerosols, rather than changes in ozone which had been our initial concern. Cloud cover is expected to increase at high latitudes, reducing UV in areas where it is already too low for vitamin D sufficiency; and cloud cover is expected to decrease in the tropics, so increasing the UV there where it is already too high for skin health. As we move away from fossil fuel combustion, the concentrations of atmospheric aerosols are expected to decrease, especially in industrialised areas of Asia. This will cause UV levels to increase over time to their pre-industrial levels.
Perhaps most importantly, ice-melt can also irreversibly affect ocean circulation patterns, leading to a weakening of the northern Atlantic Gulf Stream, an ocean current that transports energy from the equator to the North Pole. That weakening would lead to localised cooling in Western Europe while the rest of the planet bakes.
We may already have passed some of these tipping points, and so consigned ourselves to a very different and uncertain future.
Over the last 100 years, the mean temperature in New Zealand has increased by about 1°C. Temperatures in the Central Otago region are increasing too, especially the daily maxima, which have increased by nearly 2°C. Increases are much smaller for the minimum temperatures (which I find a bit puzzling. We’ll need to look into the causes for that).
At a local level, flow-on effects are also real. The number of frosty days per year has decreased and the number of warm days per year (with temperature exceeding 25°C) has increased. The region was once a mecca for ice-skating, with visitors flocking in their busloads to Alexandra from afar. But in recent years the ice on those lakes has rarely been thick enough for safety. The once popular curling bonspiels are also now a rarity. The region is surely one of the first in New Zealand to suffer adverse recreational – and hence commercial - consequences from climate change.
It must be conceded though that other factors may also be important. These include changing fashions and affluence, the trend towards skating on artificial ice rinks, and the growing popularity and access to alpine snow resorts (with their artificial snowmaking).
Heavy snowfall events like that shown below are rare at Lauder and they too may be a thing of the past (and no doubt I’ll be reminded if I’m proved wrong there). In my time at Lauder since 1979, the largest event was back in 1995 when the area remained snow-covered for weeks following two snowfalls within a week of each other. Since then there have been occasional falls, but never with snow cover persisting for more than a few days.
Just as we passed a tipping point with the emergence of the ozone hole in Antarctica around 1980, have we already passed a tipping point for extended periods of (natural) snow cover in New Zealand for all but the highest mountain peaks?
[1] The surface area of the Earth is about 510 million square kilometres, that’s 510,000,000,000,000 square metres (i.e., 5.1 x 10^14 m2, in scientific notation). So, the total energy imbalance is 0.6 x 5.1 x 10^14 watts, or 3 x 10^14 joules/second. By comparison, the energy released in the Hiroshima bomb was 63 TJ (63 terra joules), or 6.3 x 10^13 joules, which is a factor of 5 smaller than the imbalance for every second elapsed!
Next week. We turn full circle ….