Is tomorrow likely to be The Day After Tomorrow?

If you are looking for an arresting “worst case” depiction of the potential consequences of climate change, it’s tough to beat the 2004 climate disaster blockbuster “The Day After Tomorrow”.

The crux of the plot is that global warming tips the climate into a series of cataclysmic events of biblical proportions, which culminate in a new ice age.

Heading to the shops post climate change apocalypse? (sourced from Wikimedia Commons)

This premise provided an ideal basis for Hollywood to flex its special effects muscles, although the script writing budget clearly took a hit as a result.

Upon its release, prominent climate scientists criticised the film as an exaggeration.  However, the science underpinning the events depicted does have some merit.

Tipping points

The film basically depicts a climatic “tipping point” being reached followed by “run-away” climate change.

A climatic tipping point is a threshold beyond which an irreversible, self-perpetuating process is triggered which accelerates or amplifies climate change.  In the past, this process caused the desertification of the Sahara region and tipped The Earth into and back out of five major ice ages.

The apocalyptic events portrayed in The Day After Tomorrow are caused by a massive polar ice sheet completely melting and disrupting oceanic currents.  This scenario is included in many climate models and is expected to exacerbate the effects of global warming.

Albedo flip

The melting of polar ice due to global warming is being accelerated by “albedo flip”.  Albedo is a measure of how reflective a surface is.  Ice has a high albedo and reflects a significant proportion of incoming solar radiation.  This has historically provided a localised cooling effect at the poles.

Penguins reflecting upon the “albedo flip” phenomenon (image created by author.  Penguins courtesy of Pixabay)

Because open ocean reflects less sunlight than ice, disappearing sea ice amplifies the effects of global warming at the poles and accelerates melting.  This is further compounded by pools of meltwater on the surface of the ice being warmed by the sun, resulting in more melting.  It is expected that, at some stage, this process will reach a “tipping point” resulting in persistent, unstoppable, rapid melting of polar ice.

Current slow-down

The influx of cold, fresh water from melting polar ice into adjacent oceans may be weakening global oceanic currents. These currents transport heat from the equator to higher latitudes, influencing the climate in Europe and North America for example.

In The Day After Tomorrow, ocean currents grind to a halt.  As a consequence, global transfer of heat by these currents stops and the Northern Hemisphere is plunged into an ice age.

Ocean currents are propelled by the sinking of unusually dense surface water to the ocean floor in the North Atlantic.  Surface water becomes dense here partly because it cools and partly because the formation of sea ice increases salinity.   There is concern that this effect is being weakened by meltwater from the Greenland ice sheet, which is causing North Atlantic surface water to become warmer, less salty and therefore less dense.

Are oceanic currents slowing due to global warming? (sourced from Wikimedia Commons)

There is evidence that North Atlantic deep water circulation has weakened markedly since the late 1950s, although a complete shutdown is not thought to be imminent.  Some models even suggest that cooling caused by the weakening of oceanic currents could offset global warming for up to a century.

Is a sequel “stuck in the mud”?

So where does this leave the scientific credentials of The Day After Tomorrow?  Well, the script writers clearly did some homework since the film drew attention to the valid concern of melting polar ice due to global warming.  However, they were somewhat “on thin ice” in their depiction of the consequences, which are unlikely to be as dramatic, violent or immediate as those depicted in the film.

Furthermore, other climatic tipping point events could be more pressing.

One of these is the potential for large amounts of methane to be released as Arctic permafrost thaws and the organic matter it contains begins to rot.  Methane is a much more potent greenhouse gas than carbon dioxide.  Emissions due to permafrost thawing this century could be equivalent to 270 years of carbon dioxide emissions at current levels.  This would cause a sudden spike in the rate of global warming and has been described as “a slow-motion time bomb”.

Thus, if a sequel to The Day After Tomorrow is on the cards, might I suggest that the opening scene finds the hero knee deep in a rotting mammoth in the Siberian tundra.

Is a “mammoth” greenhouse gas release from melting permafrost imminent? (sourced from Wikimedia Commons)

6 Responses to “Is tomorrow likely to be The Day After Tomorrow?”

  1. Richard Proudlove says:

    Hi Rob, Sorry for the slow response. I had not come across the concept of Methane craters/sink holes so thanks for drawing my attention to this. It does indeed appear that the literature on this phenomenon is practically non-existent so there may be a research gap. Sorry I can’t be more enlightening. R

  2. Richard Proudlove says:

    Thanks for the comment Ruth. Hopefully I can answer your question as follows. Our lifestyles are disrupting natural cycles – predominantly the Carbon cycle. In very simple terms, we are releasing more Carbon Dioxide into the atmosphere than is consumed by plants or absorbed by the ocean. This additional Carbon Dioxide stays in the atmosphere for up to 200 years so is accumulating, making the planet warmer through the greenhouse effect. Note that because it stays there so long, we need to achieve NEGATIVE carbon emissions in the latter half of this century in order to stand a 66% chance of maintaining global warming below 2 degrees – a big challenge. This also means continued warming for the coming decades, so expect to see increasingly adverse effects. We have also created a new phenomenon called the “Anthropocene”, the current geological age in which human activity is the dominant influence on climate and the environment.

  3. Ruth McKeown says:

    Is our lifestyle simply exacerbating a natural cycle or is our lack of respect -deliberate or through ignorance (the tomorrow never comes approach) – creating a new phenomena ….. ??

  4. Rob Dabal says:

    Hi Richard.
    There have been a number of reports over the past few years of methane craters in Siberia.
    Do you know if there has been much in the way of further research into this phenomenon? Most of what Ive seen has been somewhat speculative, have you come across many reliable studies?
    Cheers Rob

  5. Richard Proudlove says:

    Thanks for your comment Soumya. You are correct. I believe that climate change is our most pressing issue and there is nothing which poses a greater threat to life on this planet. You might find this interesting However, if that is too depressing, this might cheer you up

  6. Soumya Mukherjee says:

    Climate change is such a topic ……… we need to act on it fast ….. Otherwise we will be extinct soon. Good piece of informative writing ….. “The day after tomorrow” is not far away.