Tag Archives: magnitude of ghg emissions reductions

Six Things That Citizens Around the World Urgently Need to Know About Climate Change In Light of Several Recent Scientific Reports

Posted on by
1

This article identifies and explains six things that most citizens around the world, although particularly those in developed countries, need to understand about climate change in light of the most recent climate change science. These six things are:

  1. The enormous magnitude of GHG emissions reductions needed to prevent catastrophic warming.
  2. The speed of GHG emissions reductions needed to prevent catastrophic warming.
  3. No nation may either legally or morally use national self-interest alone as justification for their failure to fully meet their obligation under the UNFCCC.
  4. No nation may either legally or morally use scientific uncertainty as justification for their failure to fully meet their obligations under the UNFCCC.
  5. Developed countries must legally, morally, and practically more aggressively reduce their GHG emissions than developing countries
  6. Developed countries must legally, morally, and practically help finance mitigation and adaptation programs in poor developing countries.

The need for broad understanding among civil society of these issues follows from several recent scientific reports on climate change. For instance, on October 8, 2018, the Intergovernmental Panel on Climate Change (IPCC) issued a Special Report on limiting global warming to 1.5 degrees C above pre-industrial temperatures.  This landmark report, along with several additional recent scientific studies published in the last few months including a paper published by the Proceedings of the US National Academy of Sciences on July 21, 2018, Trajectories of  the Earth System in the Anthropocene by Steffen et.al., and a paper published in mid-August of this year in Nature Communications by Anthony et. al., 21st-Century Modeled Permafrost Carbon Emissions Accelerated by Abrupt Thaw Beneath, lead to the conclusion that the international community is facing an urgent existential crisis that threatens life on Earth. Preventing this catastrophe requires the entire international community at all levels of government (national, state, regional, and local) to engage immediately in an unprecedented effort to rapidly reduce GHG emissions to net zero in the next few decades.

Although the October IPCC report on 1.5 degrees C warming received some significant notice in the US media, the recent US elections on November 6th in which climate change played only a very minor role at best, demonstrates a startling lack of understanding about the enormity and urgency of the climate threat facing the international community. Because of the immense ramp-up of programs and efforts needed to reduce the staggering threat of climate change depends on broad understanding of the scale of the problem facing the human race, and given the apparent ignorance of most citizens about the magnitude and urgency of the climate change crisis and other issues discussed in this paper, concerned citizens need to mount an aggressive educational program to inform civil society about aspects of the climate change threat that appear to be poorly understood. These issues include the following:

1. The Immense Magnitude of GHG Reductions Urgently Needed to Prevent Catastrophic Warming

The IPCC Special Report concludes that limiting global warming to 1.5°C would require rapid, far-reaching, and unprecedented changes in all aspects of society.  This is so because to limit warming to 1.5 C, CO2 emissions would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050 according to the IPCC Special Report. This means if global CO2 emissions have not fallen to net zero levels by 2050, any remaining emissions would need to balanced by removing CO2 from the air.

The Steffen et. al. paper also describes how the positive feedbacks depicted in the following graphic, once triggered could initiate other feedbacks creating a cascade of positive feedbacks, each of which could speed up the warming which is already causing great harm and suffering around the world. The paper claims this mechanism could make life on much of the Earth uninhabitable which could lead to social collapse on the global scale and ultimately to warming increases that human reductions of greenhouse gases (GHG) emissions alone would not prevent additional warming until the global system reached a new temperature equilibrium at much higher temperatures than the human race has ever experienced. In other words, cascading positive feedbacks in the climate system could result in humans losing control over reducing disastrous warming.

The Steffen et.al paper also explains how human-induced warming of slightly over 1.0 degrees C is already rapidly approaching levels that may trigger positive climate feedbacks which could greatly accelerate the warming already plaguing the world by causing record floods, deadly heat waves, droughts, increasing tropical diseases, forest fires, more intense and damaging storms, sea level rise, coral bleaching, acidification of oceans, all of which are contributing to increasing the number of refugees which are destabilizing governments around the world.

The Anthony et.al paper also explains that, contrary to common assumptions previously made by many in the international community that positive feedbacks in the climate system that could cause abrupt temperature increases would not likely be triggered if warming could be limited to below 20 C above pre-industrial levels, positive feedbacks could be initiated between current temperatures which have risen slightly above 1.10 C and 20 C. Moreover, the additional warming caused by these feedbacks could initiate other feedbacks creating a cascade of positive feedbacks, each of which could speed up the warming which is already causing great harm and suffering around the world, phenomena which threaten life on earth.

For these reasons, citizens around the world need to understand the urgent need to reduce GHG emissions to net zero as soon as possible.

2. The Speed of GHG Reductions Needed to Prevent Catastrophic Warming.

Every day that nations fail to reduce their GHG emissions to levels required of them to achieve a warming limit goal such as 2 degrees C makes the problem worse because the carbon budgets for the whole world that must constrain global emissions to achieve any warming limit goal shrink as emissions continue. Therefore, the speed that nations reduce their GHG emissions reductions is as important as the magnitude of the reductions identified by any national GHG reduction commitment. For this reason, any national commitment on climate change should not only identify the amount of GHG emissions that will be reduced by a certain date, but also the reduction pathway by which these reductions will be achieved.

The following illustration depicts two different GHG reduction pathways for reaching zero emissions by 2050. Although the curve on the top achieves zero GHG emissions at the same time as the curve on the bottom, total emissions during the period are much greater following the emissions reductions pathway under the top curve compared to total emissions under the bottom curve because the lower curve pathway more quickly reduces emissions. Citizens need to understand that waiting to reduce GHG emissions makes the problem worse because waiting consumes more of any shrinking carbon budget that must constrain global emissions to achieve any warming limit goal.

3. No Nation may either Legally or Morally use National Self-interest Alone as Justification for Their Failure to Fully Meet Their Obligations under the UNFCCC.

Because GHG emissions from every country mix rapidly in the atmosphere, all nations’ emissions are contributing to rising atmospheric GHG concentrations thus harming people and ecological systems on which life depends all over the world. The above illustration depicts that the atmosphere is analogous to a bathtub in that it has limited volume and that all nations emitting GHGs are raising atmospheric concentration of GHGs to its current concentration of approximately 407 ppm CO2 (the second line from the bottom in the above bathtub) which level is already causing enormous harm in many vulnerable countries while threatening the entire world if the atmospheric GHG concentration is raised to levels which trip positive feedbacks discussed above (represented by the upper line in the above bathtub). Thus high-emitting countries such as the US may not formulate their climate change policies on the basis of costs and benefits to itself alone. Particularly those nations that are emitting high levels of GHGs must acknowledge and respond to the devastating climate change harms they are already contributing to in other countries and particularly harms to poor people and nations that are most vulnerable to climate change impacts.  Thus in the United States, for instance, the Trump administration’s justification for withdrawing the United States from the Paris Agreement on the basis of “putting US interests first ” is ethically indefensible and tragic because of the damage the Trump climate change policy will cause outside the United States.

The following illustration depicts nations emitting high levels of GHG in red in the top half of the illustration while those countries most vulnerable to climate change impacts are indicated in red in the bottom half of the illustration.

For this reason, as a matter of law, given that nations under the UNFCCC agreed to stabilize GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. (UNFCCC, Art. 2), a nation may not fail to reduce its GHG emissions to its fair share of safe global emissions based on the cost to it because it has ethical and legal duties to other nations not to harm them.

4.  Scientific Uncertainty is Not a Legally or Morally Defensible Justification for Not Adopting Aggressive Climate Change Policy Responses.

Although opponents of climate change policies have justified their opposition on the basis of scientific uncertainty, and despite the fact that the most prestigious scientific organizations have expressly stated their conclusions about the enormous threat of climate change with increasingly higher levels of scientific probability for over 40 years, scientific uncertainty is not a justifiable response for any nation’s unwillingness to adopt climate change policies as a matter of law or morally.

Under international law, including the 1992 United Nations Framework Convention on Climate Change (UNFCCC,  Art. 3.3) which states in relevant part “where there  are threats of serious or irreversible damage, lack of full scientific certainty may not be used as a reason for postponing such measures,” and the “no harm principle”, a principle of customary international law recognized in the Preamble to the UNFCCC, nations may not legally use scientific uncertainty as an excuse for failing to take action to prevent dangerous climate change.

Also as we explained previously in 2008 in The Ethical Duty to Reduce Greenhouse Gas Emissions in the Face of Scientific Uncertainty, nations also have had a strong moral responsibility to take action to reduce the threat of climate change once it was scientifically understood that GHG emissions could cause serious harms even if the harms had not been proven with high degrees of scientific certainty.

Given, that numerous reputable scientific organizations beginning in the late 1970s,  including the US National Academies of Sciences, (See Early Climate Change Consensus at the National Academy) and five reports from the Intergovernmental Panel on Climate Change beginning in 1990 (See IPCC report timeline)  have concluded with increasing levels of certainty that human activities are dangerously threatening people and ecological systems on which life depends, nations have been on strong notice for over four decades that human activities responsible for GHG emissions are dangerous to the human community, thus nations have been on notice about the dangers of climate change for over 40 years and therefore may not legally or morally use scientific uncertainty as an excuse for failing to adopt climate change policies that will reduce their GHG emissions to levels required of them to prevent dangerous climate change.

5. High Emitting Developed Countries, Including the United States, Must Reduce GHG Emissions More Aggressively than Other Countries as a Matter of Law and Practically to Prevent Dangerous Climate Change.

Hiigh-emitting nations have a legal duty under the UNFCCC to reduce their GHG emissions faster than lower emitting nations because they agreed to:

[P]rotect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. Accordingly, the developed country Parties should take the lead in combating climate change and the adverse effects thereof. (UNFCCC, 1992, Art 3.1)

These principles were re-committed to in the Paris Agreement , Art 2.2 which  provides that:

This Agreement will be implemented to reflect equity and the principle of common but differentiated responsibilities and respective capabilities, in the light of different national circumstances.

Thus under law, hiigh emitting nations, such as the US, have a legal duty under the concept of “equity” to reduce its GHG emissions more rapidly than most other nations.  Although there is reasonable disagreement among nations about what “equity” requires of them,  formulate its ghg emissions reduction target on the basis of equity is not only required by its legal obligations under the UNFCCC, practically the US and other high emitting nations must reduce their GHG emissions by much greater amounts and faster than poor developing nations because if they don’t the poorer nations will have to reduce their GHG emissions almost immediately to near zero CO2 so that global emissions don’t exceed the carbon budget available to prevent a warming limit such as 2 degrees C from being exceeded,

  • There is a basic set of shared ethical principles and precedents that apply to the climate problem…[and] such principles… can put bounds on the plausible interpretation of equity in the burden sharing context…[and] are important in establishing what may be reasonably required of different actors.  (IPCC, 2014, AR5, WG III, Ch. 4, pg .317 )

The IPCC went on to say:

  •  these equity principles can be understood to comprise four key dimensions: responsibility, capacity, equality and the right to sustainable development (IPCC, , AR5, WG III, Ch 4, p. 318).

As a matter of law, therefore, high-emitting countries such as the United States must reduce its GHG emissions to safe levels based on equity at faster levels than other countries as any reasonable interpretation of equity would require the US to make much larger and more rapid GHG reductions than almost all other nations given that the United States (under the concept of responsibility) emitted 5,011,687 metric kilotons (kt) of CO2 equivalent emissions in 2016, second only to China’s 10,432,741 kt CO2. (Netherlands Environmental Agency), also under the concept of responsibility the United States has emitted a greater amount of cumulative CO2 emissions, that is 29.3% of global CO2 emissions between 1850 and 2002, while China emitted 7.6% during the same period, (WRI, Cumulative Emissions) making the US much more responsible for raising atmospheric concentrations of CO2 to the current level of approximately 406 ppm than any country.  Also, under the concept of equality given the US is responsible for 15.56 metric tons per capita CO2 emissions which is more than twice as much as China’s 7.45 metric tons per capita in 2016 (World Bank), as a matter of equity the US must reduce its GHG emissions much more rapidly and steeply than almost all countries.

The following illustration demonstrates why high-emitting nations must also practically reduce emissions more aggressively than other nations because it can be seen that if the high emitting nations such as China, the EU, and USA, depicted near the bottom of the illustration, don’t reduce GHG emissions muchfaster than the rest of the world, and if the international community is going to be restrained by the emissions reduction pathway needed to achieve a warming limit goal, such as the 2 degee C pathway depicted in the illustration, then there is quickly nothing left for the rest of the world. Therefore, high-emitting nations must more aggressively reduce their emissions than lower emitting nations not only as a matter of law but also to retain any hope for the international community to achieve warming limit goals agreed to in the Paris Agreement of as close as possible to 1.5 degrees C but no greater than 2 degrees C.

6. Developed Nations Have a Legal and Moral Duty to Provide Financial Resources to Assist Developing Nartions with both Mitigation and Adaptation Programs and this Financial Assistance is also Practically Indespensible to Prevent Climate-induced Harms in all Countries.

Under the UNFCCC, developed country Parties agreed to provide financial resources to assist developing country Parties in implementing the objectives of the Convention (UNFCCC, Article 4, §3). The Paris Agreement also provides that the developed countries shall provide financial resources to assist developing country Parties with respect to both mitigation and adaptation in continuation of their existing obligations under the Convention. (Paris Agreement, Art, 9.1)

Financial support of developing nation’s mitigation obligations under the UNFCCC  mitigations is not only legally required under the UNFCCC but also practically important because large-scale investments are required to significantly reduce emissions and dangerous climate change will not likely be avoided unless developing nations reduce their GHG emissions to their fair share of safe global emissions. Financial support for developing nations by developed nations is also both legally and ethically required to meet the adaptation needs of developing countries, as significant financial resources are needed by many vulnerable countries to adapt to the adverse climate change.

Climate impacts, such as sea-level rise and more frequent droughts and floods, are already having devastating effects on communities and individuals in developing countries. These impacts on developing countries are already affecting developed nations because, for instance, between 2008 and 2011, approximately 87 million people were displaced due to extreme weather events which is causing a mass migration of refugees which is destabilizing many developed nations, particularly in Europe.(Climate Change in Developing Countries, Government of Canada)  According to the World Health Organization, climate change is expected to contribute to approximately 250,000 additional deaths per year from malnutrition, malaria, diarrhea and heat stress.(World Health Organization, Climate and Health) .

Developing countries are the most impacted by climate change. This is due to many factors, including the economic importance of climate-sensitive sectors for these countries (e.g. agriculture) and the limited financial and human capacity to respond to the impacts of climate change. (Climate Change in Developing Countries, Government of Canada). The Food and Agriculture Organization of the United Nations estimates that by 2030, up to 122 million more people could be forced into extreme poverty due to the effects of climate change—many of them women. (Conflicts Fueled by Climate Change, The Guardian.)

Because climate change is already destabilizing developed countries due to refugees who are fleeing vulnerable areas of poor developing nations that have become inhabitable due to climate change-induced droughts, floods, loss of drinking water, and rising seas, if developed nations do not help finance climate change adaptation programs in developing countries, they will experience growing conflict and stress caused by vulnerable people and refugees in developing countries who are both creating conflicts in their countries and in developed countries they have or are seeking to enter. . 

Image result for climate change refugees

The following illustration depicts the number of  refugees who are fleeing or who have fled climate change.

Image result for climate change refugees

Conflicts Fueled by Climate Change, The Guardian.

For this reason, developed country financing assistance for emissions reduction and adaptation programs in developing countries is not only legally required but practically necessary to reduce climate change-induced problems and conflicts in developed countries.

By;

Donald A. Brown

Scholar in Residence and Professor

Widener University Commonwealth Law School

dabrown57@gmail.com

 

The US Media’s Grave Communication Failure On The Magnitude Of GHG Emissions Reductions Necessary To Prevent Dangerous Climate Change

Posted on by
2

 I. Introduction

This is the third entry in a series that is examining grave communications failures of the US media in regard to climate change. In this series we examine how the American media has utterly failed to communicate to US citizens about five essential aspects of climate change that need to be understood to know why climate change is a civilization challenging problem that requires dramatic, aggressive, and urgent policy action to avoid harsh impacts to hundreds of millions of people around the world.  EthicsandClimate.org has recently developed a video that summarizes these failures: Five Grave Communication Failures of US Media on Climate Change at: http://blogs.law.widener.edu/climate/2012/10/15/five-grave-communications-failures-of-the-us-media-on-climate-change/

This is the second paper that examines in more detail the issues briefly examined in the video. In the last entry we examined the failure of the US media to communicate about the nature of the strong scientific consensus about human-induced climate change. In this post we look at the failure of the US press to communicate about the enormous magnitude of greenhouse gas emissions reductions necessary to prevent harsh climate change impacts.

Subsequent posts will examine the following additional communication failures of the US media:

  •  The consistent barrier that the United States has been in developing a global solution on climate change for over 20 years.
  •  The fact that climate change must be understood as a civilization challenging ethical problem, an understanding that is of profound significance for climate change policy formation.
  •  The nature of the climate change disinformation campaign in the United States.

II. Communication Failures On The Magnitude Of The GHG Emissions Reductions Necessary To Prevent Dangerous Climate Change

 Most Americans are completely unaware of the magnitude of global greenhouse gas emissions reductions necessary to prevent dangerous climate change. If US citizens don’t understand the size and scope of the problem, they will almost certainly refuse to support legislation and policies necessary to put the United States on an emissions reduction pathway that represents the US fair share of safe global emissions.  Because, as we discussed in the last entry, the scientific consensus is so strong that the world is headed to harsh and dangerous impacts, the US media’s failure to communicate clearly about the magnitude of the problem facing the world is a serious, grave, and tragic lapse.

No US national climate change strategy makes any sense unless it is understood to implicitly be a position on the US fair share of a global greenhouse gas emissions reductions pathway capable of preventing dangerous climate change. Yet when US federal climate change legislation was under consideration between 2009 and 2010, there was almost no public discussion about whether proposed US climate change legislation would reduce US greenhouse gas emissions to levels that represent the US fair share of safe global emissions.

To understand the urgency for civilization challenging emissions reductions it is necessary to understand: (a) what temperature increases will likely trigger harsh climate change impacts,  (b) what atmospheric concentrations of greenhouse gases will cause specific temperature increases that are of concern, and (c) what quantities of greenhouse gas emissions will exceed atmospheric greenhouse target concentrations. Only then can one understand the amount of global greenhouse gas emissions reductions from business as usual that are necessary to avoid dangerous climate change.

A. Dangerous Temperature Increases

The international community agreed at a meeting of the conference of the parties under the United Nations Framework Convention on Climate Change in Copenhagen in 2009 that the world must work together to limit warming to an additional 2oC to avoid rapid non-linear impacts from climate change. The 2oC warming limit was agreed to because there is widespread agreement among the vast majority of mainstream scientists that warming of more than 2oC significantly increases the probability of harsh climate impacts.

However, catastrophic harms, at least for some parts of the world, could be triggered by additional warming of less than 2oC because there is uncertainty about how the Earth will respond to different increases in temperatures. (Athanasiou and Bear 2002) The 2oC upper temperature limit is quite controversial scientifically because, as we shall see, some scientists believe that lower amounts of additional warming could set into motion rapid climate changes that could greatly harm people around the world and increases of as little as 1oC will likely greatly harm some people in some regions.

A report, “Assessment of Knowledge on Impacts of Climate Change,” prepared by the Potsdam Institute to examine the meaning of “dangerous” climate change under the UNFCCC supported the 2°C danger limit after a rigorous analysis of climate change impacts at various temperatures concluding:

Above 2°C the risks increase very substantially involving potentially large extinctions or even ecosystem collapses, major increases in hunger and water shortage risks as well as socio-economic damages, particularly in developing countries. (Hare 2003: 89)

Yet, even this report identified very serious global and regional impacts below 2°C. In fact, this report concluded that temperature increases below 1°C threaten highly vulnerable ecosystems and between 1°C and 2 °C increase the risks of damage for all ecosystems and particularly for some regional ecosystems. (Hare 2003: 89)

There is substantial scientific evidence that even a 1.5°C temperature limit would not be sufficient to protect those most vulnerable to climate change. For instance, a recent paper by Jim Hansen and seven other authors concluded that additional warming should be limited to 1°C warming to prevent serious harms. (Hansen et al 2008) To do this, existing atmospheric concentrations of CO2 must not only not be allowed to rise the small amount to 450 ppm CO2 from current levels of 394 ppm CO2 but must be reduced below existing levels to 350 ppm CO2. (Hansen et al. 2008) According to this paper, the world has likely already shot past the level of atmospheric greenhouse gas concentrations that will lead to dangerous climate change for many. According to Hansen and his collaborators, the world has already used up all of the assimilative capacity of the atmosphere and biosphere that has been available to buffer against dangerous climate change. As a result, this paper asserts that to prevent dangerous climate change the world must not only reduce its emissions but reduce existing greenhouse gas CO2 atmospheric concentrations from the current 394 ppm to 350 ppm CO2 to avoid dangerous climate change.

And so, although the international community agreed in Copenhagen to limit future warming to 2°C, this could prove to be a limit that is too high to protect millions around the world. As one observer recently noted:

We feel compelled to note that even a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8 °C of warming so far, calling 2°C a danger limit seems to us pretty cavalier.

(Real Climate 2009)

In thinking about an upper temperature limit, many scientists are concerned with avoiding runaway climate change. That is, they fear that global temperatures will exceed a tipping point that will trigger a release of stored carbon from the biosphere, an event that would cause further rapid climate change. Runaway climate change would mean that governments would lose the ability to control future climate change that they would otherwise have through reducing greenhouse gas emissions from fossil fuel combustion and deforestation. That is, runaway climate change means that human action would be unable to stop significant temperature increase without massive geo-engineering. (Washington and Cook 2011: 30-31) This is so because, among other things, there are vast amounts of methane stored in permafrost, methane hydrates on the ocean floor, and carbon in the forests that could be released as the world warms. If the world warms too much, increased temperatures could cause huge amounts of carbon to be released that would overwhelm the quantities of carbon being released through fossil fuel combustion and deforestation. This is known to be a possibility, because such releases of stored carbon have happened in Earth’s history and caused rapid non-linear Earth temperature changes.

And so, the magnitude of greenhouse gas reductions needed to prevent dangerous climate change is understood to be the reductions from business-as-usual that will allow atmospheric concentrations of greenhouse gases to be stabilized at levels that will limit warming to between 1 to 2°C with prudence calling for a 1°C limit. We now turn to what atmospheric greenhouse gas atmospheric concentrations levels are understood to prevent warming above these amounts.

B. Atmospheric Greenhouse Gas Stabilization Goal

The amount of warming that will be experienced from different greenhouse gas atmospheric concentrations is usually referred to as the issue of “climate sensitivity.” Climate sensitivity is somewhat uncertain as there are remaining scientific uncertainties about the magnitude of the positive and negative feedbacks in the climate system.

Climate sensitivity is usually defined to mean the amount of warming that the Earth will experience if atmospheric concentrations of CO2  reach 560 ppm of CO2  equivalent, where CO2  equivalent is the metric which translates other greenhouse gases into an equivalent level of CO2 . The IPCC in its Fourth Assessment Report (AR4) concluded that climate sensitivity is likely to be in the range 2 to 4.5 °C with a best estimate of about 3°C, and is very unlikely to be less than 1.5 °C. (IPCC 2007) The IPCC also noted that climate sensitivity values substantially higher than 4.5 °C cannot be excluded. And so the temperature change that the consensus view believes is likely if all of the greenhouse gases rise to 560 ppm carbon equivalent is somewhere between 2 °C and 4.5 °C with even higher temperatures possible. The current concentration of CO2 is 394 ppm. (CO2  Now 2012)

To operationalize an upper temperature limit, the international community must set an atmospheric greenhouse gas concentration stabilization limit. Since there is scientific uncertainty about how much warming will be experienced by different atmospheric greenhouse gas concentration levels, there is significant scientific controversy about what the greenhouse gas atmospheric stabilization target should be to achieve any warming limit.

Making the calculation of emissions reductions needed at any one time is complicated by the fact that how rapidly greenhouse gas emissions must be reduced is a problem that depends upon when global emissions reductions begin. The longer the international community waits to reduce greenhouse gas emissions, the steeper the necessary emissions reductions pathway becomes. It is relatively easy to calculate the amount of additional tons of emissions that can be allowed to stabilize atmospheric concentrations at a certain level such as 450 ppm CO2 but this number will depend upon when emissions reductions begin. At any time it is therefore possible to create a budget that identifies the total tons of emissions that can be allowed before a specific atmosphere concentration is exceeded but the longer the international community waits to begin to reduce emissions, the steeper the reductions must be.

The magnitude of the challenge entailed by the need to set a greenhouse gas atmospheric concentration target becomes evident after looking at the probability of exceeding 2°C if CO2 equivalent targets are set at specific levels such as 450 or 550 ppm. In the following chart the colored lines represent emissions reduction pathways that would stabilize atmospheric concentrations of carbon dioxide equivalents at various levels. The yellow line is a pathway that would stabilize at 550 ppm. The red line is a reduction pathway that could stabilize carbon dioxide equivalent at 450 ppm. The numbers on the boxes on these two lines specify the probability of exceeding 2°C if atmospheric concentration levels are stabilized at these levels.

From this chart we therefore see that if atmospheric carbon dioxide is stabilized at 550 ppm there is between a 75% and 99% chance that the world will experience temperatures in excess of 2°C. Looking at the red line we see that even at a stabilization level of 450 ppm there is between a 45% and 86% chance that the world experience increases in temperature greater than 2°C. Because CO2 levels are already approaching 395 ppm and other greenhouse gases make current carbon dioxide equivalent levels in the vicinity of 430 ppm it becomes evident that the world is running out of time to stabilize atmospheric carbon dioxide levels in the atmospheric concentrations that would limit warming to 2°C. Because as we have seen it is possible that temperature increases as small as 1°C will create harsh impacts for some people in some parts of the world it becomes apparent that the need to reduce greenhouse gases aggressively, and dramatically, and urgently.

C. Percentage Reductions From Business As Usual Required To Stabilize Atmospheric Concentrations Of Greenhouse Gases

The startling magnitude of the challenge to the world from climate change becomes apparent upon reflection that the world is currently increasing greenhouse gas emissions  during the last decade of an average annual increase of 2.7%. (PBL 2012) Yet to stabilize carbon dioxide concentrations at about 450 ppm by 2050, global emissions will have to decline by about 60% from current levels. (Hossol 2011).  Because developing countries need to expand economic activity to escape grinding poverty according to one US White House paper, industrial countries greenhouse gas emissions would have to decline by about 80% by 2050. (Hossol 2011)

Given that greenhouse emissions are increasing year to year and that the entire world will need to reduce emissions by as much as 60% by 2050 to give any hope of remaining below 2°C, the challenge to the world is staggering. One observer sums up the situation as following:

The growth of emissions is making the task ahead more and more difficult. The longer we wait to start shrinking emissions, the faster we’ll have to shrink them to stay under budget. Here’s a visualization of what that means — some sample reduction curves with varying peak years (the four different lines are based on the four main IPCC scenarios):

(citing Anderson, K.  2011)

As you can see, if we delay the global emissions peak until 2025, we pretty much have to drop off a cliff afterwards to avoid 2 degrees C. Short of a meteor strike that shuts down industrial civilization, that’s unlikely.

This, then, is the brutal logic of climate change: With immediate, concerted action at global scale, we have a slim chance to halt climate change at the extremely dangerous level of 2°C. If we delay even a decade — waiting for better technology or a more amenable political situation or whatever — we will have no chance.

(Roberts 2011)

Although the challenge of achieving sufficient global greenhouse gas emissions to prevent 2°C is extraordinarily daunting, as we have explained above a 2°C warming limit may not prevent catastrophic harm because temperature increases more than 1°C may cause great harm.

International climate negotiations have sought to find a global solution to climate change since they began in 1990 and have struggled since then to reach a global deal among most countries to prevent dangerous climate change. Because global emissions continue to rise rather than decrease after 20 years since climate change negotiations began, the international community has lost several decades in finding a way to prevent dangerous climate change. And so, the human race may be running out of time to prevent dangerous climate change. Yet most Americans are unaware of the seriousness and urgency of the staggering problem we are facing. The US media has utterly failed to sound the alarm about the magnitude of the threat of climate change.

References:

Anderson, Kevin (2011)  Going Beyond Dangerous Climate Change, http://www.climatecodered.org/2011/12/professor-kevin-anderson-climate-change.html

 Athanasiou, T. and Bear, P. (2002), Dead Heat: Global Justice and Global Warming, Westminster, MD: Seven Stories Press, Canada.

CO2Now (2012)  Earth’s CO2 Now Home Page http://co2now.org/ (March 2012).

Hansen. J., Sato, M., Kharecha, P., Beerling, Masson-Delmotte, V., Pagani, M., Raymo, M., Royer, D., Zachos, J. (2008)  Where Should Humanity Aim? http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf

Hare, W. (2003)  Assessment Of Knowledge On Impacts Of Climate Change – ‘Contribution To The Specification Of Art’, 2 of the UNFCCC, Berlin: Potsdam Institute for Climate Research, http://www.wbgu.de/fileadmin/templates/dateien/veroeffentlichungen/sondergutachten/sn2003/wbgu_sn2003_ex01.pdf

Hossol, Susan Joy (2011)  Emissions Reductions Needed To Stabilize Climate, Presidential Climate Project, http://climatecommunication.org/wp-content/uploads/2011/08/presidentialaction.pdf

Intergovernmental Panel on Climate Change (IPCC) (2001) this multi-volume work was published as: (i) Climate Change 2001: Synthesis Report; (ii) Climate Change 2001: The Scientific Basis; (iii) Climate Change 2001: Impacts, Adaptation & Vulnerability; (iv) Climate Change 2001: Mitigation, Geneva, Switzerland: Intergovernmental Panel on Climate Change. http://www.grida.no/publications/other/ipcc_tar/

Intergovernmental Panel on Climate Change (IPCC) (2007) Climate Sensitivity And Feedbacks, in Pachauri, R., and Reisinger, A. (eds) Climate Change 2007: Synthesis Report, Contribution of Working Groups I, II, and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Geneva, Switzerland: Intergovernmental Panel on Climate Change, Available at: http://www.ipcc.ch/publications_and_data/ar4/syr/en/mains2-3.html

PBL, Netherlands Environmental Assessment Agency (2012) Trends in Global Co2 Emissions, 2012 Report. http://edgar.jrc.ec.europa.eu/CO2REPORT2012.pdf

Real Climate (2009) Hit the Brakes Hard,  http://www.realclimate.org/index.php/archives/2009/04/hit-the-brakes-hard/

Roberts, David  (2011) The Brutal Logic Of Climate Change, http://grist.org/climate-change/2011-12-05-the-brutal-logic-of-climate-change/

 Washington, H. and J. Cook (2011) Climate Change Denial: Heads in the Sand, by Climate Change Denial: Heads in the Sand, Earthscan, London and Washington

By:

Donald A. Brown

Scholar In Residence

Sustainability Ethics and Law

Widener University School of Law

dabrown57@gmail.com