Chapter 42

Sidetrack (vii) – Thin Blue Line - a chemistry experiment.

Come for a walk. 

This stroll is a bit different so you’ll have to bear with me.  Let’s pick a sunny day with maybe just a few unthreatening, white cumulus clouds floating along, nudged by a gentle zephyr.  Now lie back on the grass and look up.  Imagine a path leading straight up into the blue, blue sky.  I’ve switched off gravity for the time being so we can start to walk along this make-believe path with nothing to hold us back.  There’s no rush, let’s amble upwards at around 5km an hour, stopping to admire the view every now and then.

Within an hour we’ve passed through the hills of the British Isles, leaving behind us the ancient woodlands, the Pennine moorlands, the fells of the Lake District and the crags of the Highlands.  We’ve ascended the steep, pine-clad, snowy ridges of the Alps, pausing to put on an extra fleece, gloves and hat when we stop briefly for a warming gluhwein at a picturesque mountain restaurant.

After only another hour at 10km we’ve just passed Everest, K2 and the other Himalayan giants.  Looking back down to where we were just a few minutes ago, it’s easy to pick out the deep gorges, the tiny villages, and the steeply terraced barley and rice fields. Disconcertingly the mountainsides show clearly the signs of deforestation, of landslips, and the infiltration of spidery tarmac fingers.  Okay, it’s now seriously cold and I’ve given you thick duvet clothing and a lightweight bottle of oxygen to help your breathing.  There’s only a fifth of the life-giving gas available now but, hey, just look at the view!   You can even see a bit of a curve on the horizon.

Without gravity it’s a doddle, and before we know it we’ve reached 15km.  It’s a good spot to pause for a break, pull a sandwich and flask of coffee out the day-sac and check the weather.  There’s no need to worry about the threat of a storm; we’re above it all and can admire the enormous, towering cumulonimbus thunderclouds and feathery beautiful cirrus below us from a safe distance.  It’s not even blowy.  The express-train winds of the jet stream that race around the Earth’s middle latitudes are barely tickling our toes.  We’ve noticed quite a few aircraft over the last hour but now the only ones we have for company are the jumbo-jets, plying the trans-continental trade, their passengers oblivious to our friendly waves as they max out on the in-flight movie choices. The thinner air makes the planes seem quieter but there’s no mistaking the smell of the exhaust gasses from their jet engines.  Long after they’ve sped onwards to New York, London, Sydney or Tokyo the fumes, with their noxious mix of chemicals, linger in the still atmosphere.

It’s time to be on our way.  Ever wondered where the ‘stratosphere’ actually starts?  Well we’re entering it now and will be traversing through it during the next seven or so hours.  You might think this is going to be a boring plod, that there’s not much to see apart from the increasingly wider perspective of earth and ocean spreading out below, but one thing is abundantly clear.  From this height it becomes apparent just how crazy an idea it is to create political borders, that by drawing straight lines on a map it might be possible to separate ideologies and peoples. Such boundaries might last a few decades but inevitably they’ll be reshaped or simply disappear. Contrast these with the ageless geographical boundaries that are now so easy to spot:  mountain ranges, rivers, seas and deserts are what really create barriers to migration, to conquest, to trade.

But even these natural barriers are incapable of defending against the insidious spread of the latest enemy, some of its advances visible if we look back down over our shoulder. The billowing clouds from power-stations and factories, turning to tendrils and blown for hundreds of kilometres by the prevailing winds, carrying their cargo of micro-toxins.  Fifty years ago, when I did this upward walk as a child, it was possible to appreciate the huge swathes of dark green forests that enveloped large parts of Scandinavia, Russia and Canada.  Now these forests seem to have shrunk and lost their lushness, assaulted by several decades of acid rain.  And the cities; their ever-expanding limits and boundaries now blurred and masked by an opaque covering of smog.  And this is just the stuff we can see.

We’re high enough now that the air pressure has dropped to the point where we need to wear our pressure-suits, complete with cool-looking fighter-pilot helmets.  As an added-extra, the suit is equipped with some basic monitoring sensors and these will help us identify some of the invisible secrets of the void we’re now entering.  We don’t have to wait long for a warning bleeper to be triggered.  Wafting up through the atmosphere in increasing volumes over the last hundred years have been the gases of the modern world, their cargo of molecules released into a playground that has no control or supervision.  One of the first victims of this unregulated chemistry experiment was the ozone layer.  It’s not actually something we can see, a fluctuating zone where there are just enough ozone molecules to make this layer a life–saver.  At ground level, it’s a bad guy, a pollutant, but up in the stratosphere it reacts with ultra-violet radiation beaming in from the sun and prevents 99% of it getting through. This is important.  Life on earth doesn’t appreciate an excess of UV; it damages cells and causes cancers.  The thin protective dome of ozone is the only defence we have.

In 1976, atmospheric research revealed that the ‘ozone layer’ was being depleted by chemicals released by industry; mainly chlorofluorocarbons (CFCs) used in aerosols, air-conditioning and refrigeration products.  Concerns that increased UV radiation due to ozone depletion threatened life on Earth, led to bans on the chemicals, and the latest evidence is that ozone depletion has slowed or stopped.  It shows what can be done if we work together; all 187 countries signed the 1985 Montreal Protocol.  Anyway there’s no need for us to panic, our suits will keep the UV at bay and funnily enough, it’s not so cold now; the temperature has picked back ‘up’ to around 0 C as all the UV now being absorbed around us has warmed the air up a bit.

To lift the mood after eight hours of steady walking, I point out the 41km diving board from which the latest lunatic skydiver threw himself off in 2014.  It took Alan Eustace only 15 minutes to get back safely to the ground.  But we’re doing well going in the opposite direction and just a couple of hours later we pass out of the stratosphere and enter new territory, the ‘mesosphere’ which begins around the 50km mark. Okay so it’s suddenly getting really cold again so now’s your chance to slip into a real space suit, one with a built-in heating system circulating warm water via a clever heat-exchanger in your new backpack.

Now we have to keep our eyes open; it’s a low risk but watch out for meteorites.  This debris of ancient asteroids, mostly the result of collisions over four billion years ago, has been rattling around the solar system ever since until it has the misfortune to cross paths with the orbiting earth.  Some of it is only the size of a grain of sand, or maybe even a pea, but the mesosphere is ready for it; despite the air being so thin that it might as well be non-existent, it’s still the equivalent of a fortress wall to a meteor and they hammer themselves to a fiery, spectacular shooting-star death in their efforts to break through.  Well most of them do.  Every 50 million years or so a big bastard comes along, overwhelms our atmospheric barricade and makes it down to ground zero.  No doubt it’s quite a sight when this happens: it was probably also was the last topic of conversation for the dinosaurs.  Hopefully these days my second cousin, David Mills, (son of my Godparents Joan and Ted) in charge of the latest high-tech observatory on an Andean summit in Chile, in addition to the one he manages in Arizona, will spot such a rogue heading our way in enough time for Bruce Willis to be scrambled.

There’s something else we can’t see as we continue upwards.  Having left the ozone layer behind, there’s nothing to stop solar radiation wreaking havoc on the atoms and molecules of the upper atmosphere. The energy releases the electrons from their bonds to the atomic nucleus in a process known as ionisation and the region we are now entering is the inner boundary of the ‘ionosphere’ that stretches above us all the way to outer space.

Don’t ask technical questions but take it from me that the ionosphere is important for our modern age.  Some bright guys at the turn of the last century worked out that radio signals beamed skyward would bounce off the underside of the ionised layer and could be received back by a suitable antenna back on earth.  In 1901 Guglielmo Marconi received the first trans-Atlantic radio signal in St. John's, Newfoundland using a 152m kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall, used a spark-gap transmitter to produce a signal with a frequency of approximately 500 kHz and a power of 100 times more than any radio signal previously produced.  Suddenly we could talk, or send pictures and information, to each other anywhere on the planet without the need for a telephone line.

Meanwhile, whilst we’ve been steadily striding space-wards at 5km per hour, the earth has been continuing to roll eastwards below us at 1000km per hour.  It was early morning when we set off but now, 18 hours later as we reach 90km, its midnight and all we can see below are the illuminated cities, the network of super-highways, the flickering glow of oil refineries or the occasional flash of an electric storm.  Now around us, above us, embracing us, is another remarkable feature of the ionosphere; the spectacular aurora.  Up here the swirling clouds of ionised gas stretch outwards and upwards for thousands of kilometres.  And the colours are unfiltered by the atmosphere so we can see far more of the spectrum than just the predominant greens and blues that make it through to earthbound watchers in the far north (or south) of our planet. The best light show in the universe plays to a virtually empty house up here every night although the most spectacular evenings are reserved for those occasions when the sun kicks out one of its periodic larger solar flares.

And, after just a couple more hours, we reach our destination.  The Karman Line, at 100km, is generally acknowledged as the border between the atmosphere and outer space.  It’s taken only 20 hours to walk here.  I could run it in half the time or cycle it on my road bike in just three hours. (For comparison it would take 51 days at this pace to cycle around the earth).  A ride to this height in a Branson, Bezos or Musk rocket would have cost you several million and been over in minutes.  Sadly, we can’t stay up here for long.  When I switch gravity back on we’ll drop back earthwards, unless of course we can now quickly start travelling horizontally at about 27,000 km per hour, the speed necessary to stay in orbit.

So, what’s the point?

So the point I’m trying to make is that there isn’t much of an atmosphere separating us from outer space.  It really, really is thin, the equivalent of just 1.5% of the earth’s radius, but it contains all the chemicals and gases that life on earth needs to survive, in addition to providing a protective shield to the ongoing bombardment of various alien nasties.  It’s taken a few billion years of planetary evolution for the atmosphere to find this perfect balance and not without suffering a few shocks along the way but, for the last 66 million years, it’s provided the perfect gaseous cocktail for an infinite variety of lifeforms.  Half a century ago, on my walk, I could barely notice any signs of atmospheric distress but alarmingly, on today’s visit, every warning buzzer is sounding and flashing red.

A glance at the dials on our suit’s control panel paints a scary picture:

Carbon in the atmosphere:    420 parts per million compared to only 310 ppm fifty years ago and 50% higher than anything in the last 800,000 years.  A staggering increase in just half a century.

Here’s the problem in a nutshell, one we all know as it’s been shoved down our throats by environmental scientists and campaigners for several decades.

An overdose of carbon dioxide, and its cousin, methane, into our atmosphere traps the sun’s heat and raises temperatures, which have risen on average by 1 degree C in the last fifty years.  It doesn’t sound much but this rate of change is enough to start breaking down the planet’s equilibrium far more effectively than another ice-age phase or sustained period of volcanic activity.  Consequently, the ice caps and glaciers are rapidly melting, losing Earth’s ability to reflect heat from the sun back into space and raising the level of the oceans that are now also having to bear an increased share of carbon absorption.  A knock-on of all this is a rise in acidity which is currently a major factor in the death of coral reefs, declining fish stocks and algae blooms.  And as the oceans warm, they add to the heating impact on the atmosphere near the surface and weather systems, broadly predictable for decades, are suddenly becoming disrupted and volatile.  In addition, when the permafrost starts to melt, that too will release a massive dose of trapped carbon into the atmosphere, with a much greater impact than what we’ve already managed from our consumption of fossil fuels over the last century.  Great eh?

If temperatures keep rising we really are screwed.  Just remember that the great extinction 250 million years ago took out 90% of all life on the planet and was linked to a temperature rise of 5 degrees.  Apparently, if we reach 2.5 degrees, things will spiral out of control and there’s no way back, hence the big focus on 1.5 degrees at the 2021 COP conference in Glasgow which is the supposed level that it still possible to slow down and start to turn the climate-change super tanker.

Right now our leaders are only talking about applying the brakes, maybe just giving them a tweak, but someone’s forgotten to tell the guys in the carbon-generating engine room that it’s not just about reducing industrial and transport emissions. Chopping down the forests is a double whammy - bang goes a natural carbon bank so even more of the stuff is freed up and bang goes one of the most efficient carbon gobblers that can help actually reduce the amount.  And turning forests into pastoral grazing for methane-producing livestock fed on nitrate-enhanced foodstuffs is just the icing on the cake.

But you know all this, don’t you?

Maybe I should offer a ‘walking tour’ to those in power.  Lead them up here, to the edge of space, let them float around for a few hours and hopefully get the message across; the one that we, along with the astronauts, scientists and campaigners having been trying to tell them.

From this vantage point they can’t fail to appreciate that our atmosphere, the ‘thin blue line’ wrapped around our planet, contains all we need for survival. What they might also understand is that it’s a closed system; there’s no emergency oxygen tank anywhere. It’s like we’re stuck in a giant petri dish or test tube with no way out and some mad professor is tipping in all sorts of chemicals just to see what happens. If we can’t find a way to stop him buggering it up, then there’s no way back.

Gravity-free ramble.                                                                                              Ozone hole - a rare  success .                                                                                     Thin blue line.

CO2 level changes since we walked on the planet.