Skip to content

Getting Real for Earth Day


On April 22nd 1970 the first Earth Day was celebrated across the United States as students and mentors in schools and universities across the country participated in teach-ins and demonstrations about the environmental crisis. Some 20 million Americans participated in events at tens of thousands of locations across the country. Earth Day grew from there, becoming global in 1990, and will be celebrated again in just a few days’ time. Since 1970, Earth Day has been regularly the largest secular day of protest in the year.

This year, the official theme for Earth Day, April 22, seems to be about plastic pollution, but I think it is a time to reflect on how well we are caring for this planet, and then try to do better. Lots of discouraging news this year plus one bright spot – our population is going to get smaller sooner than anyone expected.
Image © RELX SDG Resource Center.

I think that is a reasonably accurate description of the beginning and history of Earth Day. I have friends who remember the first Earth Day and they will correct me if I have erred. But in my last post I was reflecting on how what we know of the world is only a model of reality, a model which may not be accurate. Of course, what I did not say in that post is that evolution has had millions of years to select for sensory systems capable of creating reasonably accurate models of reality – with seriously imperfect models you don’t get to survive very long. But I also am confident that if we were to poll a random assortment of people this week and ask them to identify the event called Earth Day and tell us a bit about its history, many would not be able to tell us much. Because Earth Day has become routine, something we are reminded of each year by those who like to remind, but something that most of us do not think too deeply about.

Some people take Earth Day seriously each year, plan events, and at minimum, think about our many environmental problems and vow to do better or do more to solve them. Many people scarcely do more than note its passing on their devices. I think Earth Day is a great day on which to reflect on how well we are doing in the battle to repair and sustain this planet. In this, I have a reality in which Earth Day is a more important event than is the case for many other people. But my reality is also a sombre one, and while I celebrate Earth Day, I do so with a sense of loss, a heavy dose of the ecological grief that strikes me ever more frequently these days. It’s time to get real about Earth Day.

What’s changed since 1970?

Our global environmental crisis has got worse in the 54 years since the first Earth Day. A lot worse. In April 1970, the concentration of CO2 in the atmosphere above Mauna Loa was 325.74ppm. In March of 2024 it was 425.04ppm, 100ppm or 30% greater. And the curve describing the accumulation of CO2 since 1958 when the instruments were first put up on top of the mountain continues to slope upwards.

On April 5th, NOAA confirmed that the CO2 concentration had again increased in 2023 (along with the concentrations of methane and nitrous oxide, two other important greenhouse gases), and showed that, if anything, the rate of increase continues to rise also. We all know why there is more CO2 up there now; at least those who accept that our burning of fossil fuels puts CO2 into the atmosphere do. In other words, all our efforts to shift towards non-polluting forms of energy have had zero effect on the rate at which we are adding to the warming of this planet!  All our efforts have done is ensure that our growing economy, and its growing use of energy, has not increased even more the rate at which we are dumping CO2.

Is it any surprise that our climate is getting warmer and more unpredictable? 2023 was the warmest year on record, 1.18oC above the average for the 20th century, and 2.43oC above the average for 1850 to 1900 – a time when our technological civilization was just ramping up. Putting things into a longer-term perspective, 2023 was the warmest year ever experienced by Homo sapiens since it evolved 315,000 years ago in Africa.

While the world averaged 1.18oC warmer than the average for the 20th century, climate change is more extreme in some parts of the planet than others.  In general, more tropical latitudes are warming more slowly than more polar ones, and for Canada, the average temperature in 2023 was 2.0oC above the 20th century average – almost twice the global warming. This was particularly evident in northern Canada with record high temperatures recorded at Northwest Territory and Yukon sites last summer.

The biggest impact of the warm year in Canada was the serious escalation in wildfire frequency and extent across the country, which led to severe air quality problems in Eastern Canada and down as far as New York City. The sheer extent of Canada’s wildfires in 2023 can be seen in the fact that not only was that year the worst, in terms of hectares of forest burned, but the worst by far.  In 2023, there was twice the area burned than in any previous year. I personally found air quality hampered my life here in Muskoka for the first time ever, and I know that serious fire seasons are going to occur in future years also. This has serious implications for the lives of residents in fire-prone habitat – like most places outside cities. It also has serious implications for Canada’s greenhouse gas reduction plans, because Canada had been counting on modest improvements in the sequestering of carbon by better management of our extensive forests.  Now those forests are shifting into carbon emitters because of the more extensive fires.

Worldwide, climate warming has led to alarming increases in the severity of storms and to increases in the rate of melting of polar ice. In the Arctic, sea ice extent was again low through 2023, but not at record levels. The record low year in the Arctic, 2012, has yet to be matched although 2023 came very close.

Graph showing sea ice extent in the Arctic, extracted from the Charctic Interactive Sea Ice Graph provided by the US National Snow and Ice Data Center. 2023 (green) is close to, but less extreme than the record minimum set in 2012 (red) and well below the 1981-2010 long-term average.

In the Antarctic, sea ice extent was markedly low throughout most of 2023, setting a new minimum, and in mid-August was more than 2.6 million km2 less than the 1981 to 2010 average.

Graph showing sea ice extent in the Antarctic, extracted from the Charctic Interactive Sea Ice Graph provided by the US National Snow and Ice Data Center. 2023 (red) is noticeably lower than 2022 (orange) and well below the long-term (1981-2010) average.

In March 2024, scientists from the Australian Antarctic Program and University of Tasmania published a study of the pattern in sea ice extent in Antarctic waters from 1979 to 2022. They report what they term a regime shift in summer sea ice extent around 2014-2016, yielding much greater variability in ice extent and much lower summer minima in km2 of ocean surface covered.

The record of summer ice area (SIA) in the Antarctic from 1979 to 2024 shows an abrupt change with markedly less ice present during summer months beginning around 2016. The reasons for this are not yet understood, but statistical changes in variance, degree of autocorrelation and sensitivity to factors such as air temperature suggest there has been a fundamental change in how sea ice is propagated and preserved from month to month.  A warmer ocean may turn out to be a big part of this change. Figure © W Hobbs and American Meteorological Society.

While melting of sea ice does not raise sea level, the same patterns of extensive melting are occurring on glaciers throughout the world. These meltings do raise sea level as well as reduce summer river flows in ways that are going to become critical for agriculture in many parts of the world.

The Guardian recently reported on a whole suite of climatic changes taking place in Antarctica, all tied in some way to warming, all interconnected and ramifying to cause such things as catastrophic losses of Emperor penguin chicks in 2022 and loss of the CO2 sequestering that occurs when krill eat algae that live under sea ice and then poop out pellets that take that carbon safely to the bottom of the ocean where it can be buried in sediments instead of being released back to the atmosphere. We live in a complex and interconnected world!

What most people don’t seem to know is that many of these knock-on effects of warming are going to continue for decades or centuries even if we were to magically achieve zero emissions in 2024. For example, sea level is going to continue rising for several hundred years even if we stop the warming now (and we are not going to stop the warming any time soon given present performance by many countries including my own Canada).

This means that we are not entering a new normal of, for example, higher sea level. Instead, we are entering a time of continually rising sea level, year by year for several hundred years; a time of continually changing climate.  Telling people that Miami will experience about 15cm of sea level rise by 2040 is one thing. Showing them that the same trajectory that produces that 15cm, produces 1.5 meters of sea level rise by 2100, and the trajectory continues up from there – that’s a different thing.  Much of Miami will be under water by 2060. And there is enough potential in glaciers that are melting and water that is expanding as it warms for sea level rise globally to top out well above 20 meters although that is a couple of centuries away. Since the dawn of civilization 8000 years ago, humanity has not had to plan for a continually changing climate. In fact, it was the predictability of climate that, arguably, enabled civilization to develop. We live in a new and changeable world.

Another slow knock-on effect is the change now happening to forests across the world. In Canada, as well as greatly increased incidence of wildfire, there will be the inexorable replacement of trees suited to a more northerly climate by ones suited to a warmer climate. With trees not being particularly mobile, and with forests already cut up and separated by various forms of human land use, the migration north that needs to occur may have to be assisted by us, by using southern species when reforesting. Of course, there is also the possibility that forests will get replaced not by southern forests but by grasslands or deserts. Because the warming is also causing dramatic shifts in the hydrological cycle and in many parts of Canada, certainly the central Ontario region where I live, summers are becoming dryer as well as warmer. We have created a much more challenging environment for plants.

Slow effects of climate change, which humans can surely navigate relatively easily if we plan ahead (which clearly may not happen!), are one thing. Changes which happen more quickly but hidden from our eyes are quite another. The worldwide decline in number of insects is such a change.

Loss of biodiversity

Are you old enough to remember car trips in the summertime (in 1960-1970 North America, Europe, Australia at least)? Once you got outside the cities, you had to stop at gas stations every few hundred kilometers even if you did not need to fill up, because you had to clean the bugs off the windshield. Not anymore, and it is not because cars have become more aerodynamic so the bugs stream safely by. It’s because there are fewer insects flying.

This global decline is complicated when looked at closely, probably because there are many drivers of reduced insect abundance that vary in their importance from place to place and among insect species. Most estimates range from 1% to 2% per year, which can lead to massive loss over a decade or two. Two recent articles with a global focus on insect biodiversity decline provide hints of this complexity. A 2023 article by R. van Klink and others in Biological Letters stresses that downward trends vary among taxa, among regions and among major habitat types. In December 2023, an article by M. Gossner and others published on-line in Nature reports that abundant species are the ones that have declined most severely in numbers. Both articles discuss drivers of the declines in abundance and diversity, identifying expanded human uses of land and climate change as the two primary drivers among a suite including pollution, increased numbers of invasive species, and widespread pesticide use among others.

And the decline in insects is just one part of an overall reduction in the numbers and diversity of all living species other than humans, their crops and their domesticated animals. We happily discuss the possibility of using clever genetic engineering and in vitro techniques to produce more Northern White Rhinos (only two individuals of this species survive) while blissfully ignoring the fact that humans have decimated most other species on this planet.

The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) 2019 global assessment report on biodiversity and ecosystem services includes in its Key Messages for policymakers the statement, “The average abundance of native species in most major terrestrial biomes has fallen by at least 20 per cent, potentially affecting ecosystem processes and hence nature’s contributions to people; this decline has mostly taken place since 1900 and may be accelerating.”

It also reports, “Seventy-five per cent of the land surface is significantly altered, 66 per cent of the ocean area is experiencing increasing cumulative impacts, and over 85 per cent of wetlands (area) has been lost.” And, “Approximately half the live coral cover on coral reefs has been lost since the 1870s, with accelerating losses in recent decades due to climate change exacerbating other drivers. The average abundance of native species in most major terrestrial biomes has fallen by at least 20 per cent, potentially affecting ecosystem processes and hence nature’s contributions to people; this decline has mostly taken place since 1900 and may be accelerating. In areas of high endemism, native biodiversity has often been severely impacted by invasive alien species. Population sizes of wild vertebrate species have tended to decline over the last 50 years on land, in freshwater and in the sea.” Anybody sensitive to the many ways in which nature benefits human societies will find very little encouraging news in this comprehensive document. And yet we mostly continue to ignore the coming problems as biodiversity plummets.

It is not just the natural world that is changing. Our human world is riddled with strife, famine, and mass migration of desperate people on the one hand, and growing autocracy on the other. These societal and political changes may even be linked to the assault on nature in which humans are engaging. Certainly, climate change is leading to crop failures in some regions which then give rise to strife and famine. And desperate people, weak and fearing they have no real future, can often turn to autocrats who promise they can fix all that ails us.

So, where do we stand in 2024?

It is not an exaggeration to say that the state of the world is now much worse than it was at the first Earth Day in 1970. As I look around, I see few bright sparkles of hope, however the evident decline in human birth rates in most parts of the world is a major such sparkling sign that we should celebrate.

Projected size of the global human population under five scenarios, most depicting a markedly sooner transition from increase to decline than does the projection by the UN Population Division. The ‘reference’ line is the best estimate with a peak at 2064. Image © S Vollset & Lancet.

On 2nd April, Science used its news site to report on a new study in Lancet on the state of the global human population. This study, by SE Vollset and colleagues from the Institute of Health Metrics and Evaluation at University of Washington, is the latest report of an even earlier date for the global human population to reach its maximum and begin to decline.  While the UN Population Division has projected a peak above 10 billion and a decline sometime after 2100, Vollset and colleagues show that the peak is likely to occur by 2064 at a population of 9.73 billion, with average lifetime fecundity of 2.1 (the number of children needed for exact replacement of parents) achieved by 2034. They also show that if the Aichi targets are reached worldwide for education of girls and for free availability of contraception, average lifetime fecundity of 2.1 will be reached by 2030, and the population will have declined to 6.29 billion at 2100 – a population smaller than the one we have now! With fewer of us, our footprint should be smaller!

Maybe humans are having fewer children now because we are bright enough to see what we have been doing to the world? Well… enticing as that idea may be, I think things may be a bit more complicated than that. In fact, it is even possible that our despoliation of the planet is a factor in our more rapid than expected loss of fecundity because of inbuilt responses to stress and crowding. Certainly, if we were behaving intelligently we would have reduced the growth of our own population long ago.  But then we also would have managed to stem our production of greenhouse gases way before now! We intelligent apes – that is what sapiens means after all – are apparently not intelligent enough to see that trashing nature as we have been doing ever since we tapped into the enormous stores of energy contained in fossil fuels is not a good strategy long-term.

So, what should we do this Earth Day? I suggest five things: 1) Reflect on the impossibility of building a continuously expanding economy on a finite planet. 2) Reflect on the mistakes we have made while pursuing that false goal. 3) Reflect on the fact that we, collectively, are still making those mistakes because we seem incapable of living within the means of the planet to provide for our needs. 4) Especially reflect on the possibility that if we can accelerate the extension of education to girls and women everywhere, and keep contraception as widely available as we can, then maybe we can reduce our overall pressure on this beautiful planet we inhabit. And finally, 5) let us all commit to talk to our friends and especially to younger generations about how it is possible to build wonderfully rich, healthy, satisfying lives in culturally rich esthetically satisfying societies that do live within the limits nature sets. Would it not be wonderful if on Earth Day of 2078 (54 years from now and 108 years since the first Earth Day) we could look around and report that some of our mistakes have been repaired, and that we are well on the way to repairing many others. That we have in fact become stewards of this planet instead of its pillagers.