Climate Change: What Happens after 2100?

2011•11•16 Gregory Trencher University of Tokyo

We all know that the carbon legacy of our fossil fuel-based lifestyles is bequeathing a climate crisis to billions of people into the future. But when we say “future”, just how far should we be thinking ahead? As far as 2050? 2100? Or a little bit further, maybe as far as 2500 and beyond?

You may have already noticed that future climate projections used by the international scientific and political communities generally go only as far as the year 2100. The simple reason for this is that it is impossible to predict with any degree of accuracy just how much greenhouse gases are going to be released in the next few centuries, and just how much this is going to affect the climate.

But don’t be fooled. This does not mean that climate change will cease to be a problem in the years lying beyond the upper reach of our most cited climate forecasts. The shocking truth is that climate change has only just begun. Regardless of future emission trends, the CO2 footprint from our brief passage on Earth is going to remain in the climate system and impact the well-being of all terrestrial life forms for what could almost be considered an eternity.

The majority of C02 emitted from burning a single tonne of coal or oil today will be absorbed over a few centuries by the oceans and vegetation, the remaining 25% will still be affecting the climate in 1,000 years.

According to scientist David Archer, whose research is often featured in the renowned Nature magazine, the C02 that we are emitting from fossil fuels today will still be affecting the climate in many millenia from now. His conclusion is that even though the majority of C02 emitted from burning a single tonne of coal or oil today will be absorbed over a few centuries by the oceans and vegetation, approximately 25% of it will still be lingering in the atmosphere in 1,000 years, and 10% still remaining and impacting the climate in 100,000 years time.

It will then require thousands and thousands more years for its complete absorption through the natural climate cycle. As Archer puts it, “the climatic impacts of releasing fossil fuel C02 to the atmosphere will last longer than Stonehenge, longer than time capsules, longer than nuclear waste”.

The Copenhagen Diagnosis

Some of this future devastation is briefly discussed in the recently updated Copenhagen Diagnosis — a report authored by 26 leading climate scientists with the aim of updating the world on findings since the publication of the IPCC Fourth Assessment Report in 2007. According to this Copenhagen Diagnosis, regardless of when a peak in global emissions finally occurs, the global temperature cannot be expected to stop rising until several centuries later, due to the extremely long life cycle of C02.

The carbon that we are releasing into the atmosphere today is in the process of ‘programming’ a potential 2-5 metres of sea level rise by around the year 2300.

But that’s not all. The report also states that “even a thousand years after reaching a zero-emission society, temperatures will remain elevated, likely cooling down by only a few tenths of a degree below their peak values.”

In other words, whatever the mitigation efforts of future civilisations, climate change is here to stay. Only after this extremely long period of forced warming — far more than the history of modern civilisation since the Scientific Revolution — will climate change slowly begin to ‘reverse’ and the planet will at last embark on a cooling trajectory, the report explains.

But long before this ever happens, humanity must prepare itself for an inland retreat and a constant battle against rising seawater that will continue for hundreds and hundreds of years into the future. The phenomenon of sea level rise resulting from thermal expansion (sea water expands as it warms) and melting ice sheets in Greenland and Antarctica is the perfect illustration of climate inertia in action.

As may be seen from the graph below, showing estimates from three different models, it takes several centuries for the oceans to fully respond to a warmer climate and altered carbon balance. As a result, the carbon that we are releasing into the atmosphere today is in the process of ‘programming’ a potential 2-5 metres of sea level rise by around the year 2300.

What’s more, the authors of the Copenhagen Diagnosis warn that sea level rise will continue for many centuries after the eventual stabilisation of global temperature (and therefore beyond the upper limit of this graph too). This is no doubt going to have a devastating impact upon future cities, towns, agricultural areas and freshwater resources located near coastal regions. (The Centre for Remote Sensing of Ice Sheets has some detailed images available of the areas of the globe most threatened by sea level rise.)

Small decisions, huge consequences

With this geological mayhem scheduled to take place over the next several thousand years, the decisions that we are making (read: not making) in the present take on a new light. Clearly we need to expand the time scale with which we assess the full implications of the climate crisis beyond the current century. Once humans turn up the planetary thermostat by 2°C (the goal to which the international community is committed at present, albeit very optimistically), there will be no turning it back, save a trend towards planet-altering geo-engineering.

Instead, the temperature control will be locked in and all life forms on Earth will be pressured to adapt for thousands of years. The climate change-driven ecological destruction that we are witnessing today — immeasurable loss of human life, plant and animal species caused by natural disasters such as floods, droughts, wildfires and heat waves, the disappearance of vast snow caps, glaciers and almost half of the Arctic — is the result of a mere 0.8°C rise in average temperature since 1800. We can only imagine what a further 1.2°C rise before 2100 will mean for the Earth’s already vulnerable ecosystems and at-climate-risk communities.

Future ethics

The planet is the ultimate ‘global commons’. It belongs to neither a particular individual nor a particular nation. Nor does it belong to a single generation such as us, our children or our grandchildren. Instead, it belongs to all living creatures both alive now and in the future. Just as all of humanity is connected ‘horizontally’ across the globe, so too are all past and future life forms bound ‘vertically’ in a continual unfolding of the story of life.

Yet the political and economic institutions of our civilisation are fixated on enjoying the present and unable to account for the consequences of our actions on tomorrow. This may be all too easily observed in our financial behaviour, where individuals, corporations and governments are forever borrowing from the future in order to improve the present.

In the same way, the fossil fuelled party of our capitalist global civilisation is in the midst of a financial and ecological borrowing frenzy from the future. And not only are the spoils of our mastery over nature enjoyed by only a minority of the planet, but in geological terms, they are being consumed within an extremely short time-span.

In a crisis of modernity that could also be re-interpreted as one of ethics and values, how should we reframe our choices and actions in the present, in light of tomorrow?

Surely it is just a matter of standing in the shoes of all future citizens and asking ourselves what sort of planet they would like to live on. Surely our descendants, hundreds and thousands of years into the future, would wish for, and have a right to, the same stable climate and ocean levels that have allowed the attainment of such an advanced and flourishing civilisation today.

It is none other than this consideration for future human beings and other life forms that should form the yardstick by which we set our mitigation targets — not merely what is politically and economically feasible for the industrialised world today.

Creative Commons License
Climate Change: What Happens after 2100? by Gregory Trencher is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.



Gregory Trencher

University of Tokyo

Gregory Trencher was previously an intern for the Education for Sustainable Development Programme at UNU Institute of Advanced Studies in Yokohama, Japan. He is currently researching the potential of research universities to address the climate and sustainability crisis as part of a Ph.D. at the Graduate Programme in Sustainability Science at the University of Tokyo. He is also director of the Environmental Learning Institute, a climate change educational initiative for Japanese businesses and corporations.

Join the Discussion

  • Alan

    This article deserves to be widely read – and deeply absorbed into our individual and collective consciousness.

  • Kravcik Michal

    my group created initiative Košice Civic Protocol on Water, Vegetation and Climate Change ( on the bacground of New Water Paradigm – Water for Recovery of the Climate ( .
    In this moment Slovak Government implementing program on this initiative, with start in this year (  

  • Gregtrencher

    Thanks to you both for leaving your valuable
    comments. To tell the truth, I kind of feel terrible for writing an article that
    has such a dark message at its core: that whatever the mitigation efforts of future
    generations, the carbon legacy of our brief passage on Earth is going to plague
    the wellbeing of billions and dramatically alter the geography of the globe. I
    am well aware that many of our readers are past the ‘what’s the problem stage?’
    and already at the ‘what can be done?’ stage.

    My position is simply that we act after we grasping the truth, and the whole
    truth. The danger of course is that if we don’t seize the full ramifications of
    our failure to solve this crisis today, then our solutions will not be of the
    scale that is needed, and they wont be deployed rapidly enough (as is currently
    the problem).

    I also agree with Alan’s comment the other day, that nothing sort of a new way
    of perceiving reality (‘software’) is going to permit us to fully address the real
    problem at the heart of our civilization, but I also think that ‘hardware’—cheap
    and accessible to all—is equally, or almost, as important.

    For some good news about hardware, I recommend this German film, which I am going
    to see on Thursday. Its about the renewable energy revolution that is unfolding
    across the globe right as we speak.


    • Alan

      Well, Greg, I’m sure being the bearer of bad news could naturally make you feel kind of terrible, but as you say, we need to know “the whole truth” if we are to adequately calibrate and respond to the reality of our situation, and it is for that reason that I believe messages such as your article – which pull no punches – play a critical role in forcing people, albeit uncomfortably and inconveniently, to wake up to what we are doing to our selves and our planet’s other inhabitants.

      And the truth seems to be that we simply don’t have time to indulge in being leisurely about how we deal with climate change…we’re being called to respond quickly and decisively, and collectively. And yet…we arguably don’t know what to do that will enable us to address climate change at the required scale while simultaneously keeping an energy-intensive global high-tech economy growing at a sufficient rate to clothe and feed 7 billion+ people, all on a finite earth with rapidly depleting resources and degrading ecosystems. Faced with these variously interlocking Faustian bargains, it makes perfect sense that we tend to flee from the awful truth about the future climate we’re bequeathing to countless future generations.

      If the environment is the backdrop against which we’re playing out our human drama, it seems we’re tearing down the curtains and burning the set while forgetting we utterly depend on them to make meaning.

      One reason I’m a broken record about the “software” approach is that none of the hardware approaches will work unless we achieve the necessary critical mass of new thinking, and remembering. Ironically, even the German film you linked to summarizes its message on the home page by saying: “The transition is possible. The only precondition: We need to want it!”

      Clearly, any binary “this vs that” approach isn’t realistically going to suffice. We need both/and, software and hardware together, in varying proportions as necessitated by the realities of our varied interests, inclinations, and predilections. I totally agree with you on that.

      And, finally, because I’m hedging my bets about sufficiently widespread social change actually happening given entrenched interests and inertias – and because, too, I’m definitely a skeptic about technical fixes saving the day – my inclination is to lean toward software.

      Indeed, when no one really knows what to do, I’d suggest that it is  a very good time to become friends with not-knowing. That friendship changes everything.

  • Craig Pierrot

    Hey, first-time reader, so I have no idea what this site even is or is normally about, lol, but I must say, thank you for writing this, I think, rather sobering and realistic view of the damage we have already done to our planet and what it’s results will be.

    My question, tho: I saw on DemocracyNow the other day reports of a new scientific study recently published in the scientific journal “Nature” about how these larger thunderstorms that’re a direct result of anthropogenic climate change were doing something probably almost NOBODY predicted: pushing all the CFC’s and such that we ALREADY put into the atmosphere higher up into the atmosphere FAR FASTER than anyone had previously predicted, resulting in the destruction of the Ozone layer also FAR FASTER than anyone had previously predicted.

    What do you think of these reports? I don’t think this is an issue dealing with Anthropogenic Climate Change that anyone is really talking about…but SHOULD BE.

    So yeah, what do you think of these reports of the larger thunderstorms caused by climate change causing the destruction the ozone layer far faster than anyone before had previously expected? Thanks!

  • If plants remove CO2 from the air, why would it continue lingering in the air? And if they don’t remove all the CO2, can’t we use carbon air capture or scrubbing to remove it?

  • Winged Wheel

    Great article, though my timing is obviously off. A few items I felt were left untouched though. Primarily, is there a study relating to the impact deforestation has on our planets ability to “scrub” CO2? The studies you referenced on the rate of CO2 dissipation over time would likely be inaccurate because our planets ability to clean itself is being destroyed simultaneously while carbon emissions increase. Just wondering if that fact is accounted for in those three studies. Secondly, why was fossil fuel so focussed on (in terms of planetary impact and carbon emissions) while animal agriculture not mentioned? Simply put, the propagation of livestock accounts for more emissions, more deforestation, more desertification, and generally more impact than any other single source.

    • Greg Trencher

      Thanks for this message. Your timing was impeccable too, after all, CO2 lifetimes are on the millennial scale! I am not aware of any studies personally that account for the reduced CO2 absorbing capacity of forests over the millennial
      time scale when considering CO2 lifetimes, but one commonly cited concern the is the reduced capacity of the
      ocean surface to absorb CO2. Currently it absorbs around 1/4 to 1/3 of human
      emissions and this will be lowered over this century (and thereby over hundreds
      of years after that due to thermal inertia) due to warming and acidification. A
      colder ocean absorbs more CO2, and increased acidity also decreases CO2 absorption
      activity. The point you raise about animal agriculture is really important. There
      are many figures floating around on how much agriculture/land use change (including
      deforestation) is contributing to global GHG emissions, but a fairly good
      estimate seems to be around 20%. Its not as big as other figures out there such
      as 30% due to assumptions in calculations and different warming strengths assigned
      to methane over different atmospheric lifetimes. Regardless, this is huge, and livestock,
      especially beef, is making up the bulk of this. You can see several key studies on this topic
      linked here:
      Regardless of the source of CO2, the fact that a large proportion of emissions
      from today will persist in the atmosphere over several centuries and even millennia
      is the most important long-term implication of the climate crisis. Yet it is
      rarely understood or acknowledged in international climate negotiations which
      are built on the assumption that they can solve the problem. Hansen et al acknowledge long-term impacts
      hence their support for the 350ppm target (
      As the need to bring atmospheric CO2 levels back to 350ppm (and even
      pre-industrial levels) is increasingly acknowledged, this means that there will probably
      be an eventual need to drawdown some of that CO2 back into the oceans, soils, forests
      and geological reservoirs through whatever means we care to risk (i.e. carbon
      dioxide removal types of geo-engineering). The potential of afforestation to achieve this alone is unfortunately limited.

  • Christopher Scott

    Hi Gregory – very good analysis. Just curious if there is more recent climate data that impacts this scenario (i.e. feedbacks, etc.)

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