Emissions pathway to return global warming beneath 1 degree Celsius

Leading climate scientist Bill Hare has published the first emissions pathway to date that brings expected global warming beneath 1°C, albeit after peaking beneath 2°C and on the scale of centuries.

This is an immensely significant research topic for coral reefs as a rise in mean global temperature of 1°C appears to be the highest target that should be set if coral reefs are to be protected from serious degradation (see previous Climate Shifts post here).

Figure 2-1 depicts the global emissions pathway that Hare (2009: 25) suggests “is plausible technically” and “goes beyond the technically and economically feasible pathways published elsewhere”. It requires getting fossil CO2 emissions down to close to zero in 2050 and being carbon negative thereafter – a commitment to action that spans centuries.


Hare (2009: 27) suggests that under this emissions pathway “global temperatures should peak below 2 degrees Celsius around mid-century and begin a slow decline, dropping to present levels by the last half of the twenty-third century.”

The means of achieving such an emissions pathway, including being carbon negative after 2050, are discussed by Hare and other authors in subsequent chapters of the Worldwatch Institute publication, ‘State of the World 2009‘. This report is peer reviewed, but Hare will hopefully publish his new modelling in a peer reviewed climate journal shortly to improve its acceptance in the scientific community.

Hare (2009: 25) acknowledges that achieving negative CO2 emissions on a global scale will be extremely difficult and “evaluation of the implications of the technologies required to achieve this are only just beginning.”

Hare’s emissions pathway builds on the recent publication by Jim Hansen and his colleagues which argued “If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm, but likely less than that.”

The ambition of the emissions pathway suggested by Hare (2009) is far beyond any contemplated in the mainstream policy debate at present but it is likely that such radical proposals will become much more prevalent in the future.


4 thoughts on “Emissions pathway to return global warming beneath 1 degree Celsius

  1. Along with the emission pathways we need the political consensus.

    Global cap and share is difficult to organise as sovreign nations do not want a supra-national carbon authority selling permits on sovereign national territories. At the same time Developed countries are not moving on CDM or other initiatives for delivering agriculture or forestry projects – the most important types of projects for a net zero energy life-style in developing countries as well as of course in developed countries.

    A quick way to achieve the transformation of developing and developed countries that will have the support of developing countries is to adopt a partnership approach to sustainable development. The approach is based on an underlying cap and share model but asks developing country partners rather than a supra-national authority to take the responsibility of selling the permits.

    This scheme could be written into the Kyoto Protocol under Annex B, listing the number of permits available from each developing country in each year in the period 2010 to 2030 and mentioning that Annex 1 countries do not have permits but must buy them if they wish to continue to emit.

    The aim of this partnership arrangement is to jointly achieve a net zero global warming pollution level and net zero energy life-stye for the citizens of developing and developed countries at a comfortable life-style level by 2030.

    Every year until 2030 developing countries sell the permits at a rate of one thirtieth of the amount they need per person to meet their development needs. At the end of the period they will thus have raised all the money they need. The price per tonne of carbon dioxide equivalent covers the cost of the required agricultural and forest development, water, housing, transport and electricity infrastructure in developing countries in this period.

    Developed and developing countries develop their economies to a similar net zero global warming pollution and net zero energy standard and share technology kno-how and experience. By 2030 the citizens of all countries will have a similarly comfortable life-style at net zero energy and net zero global warming pollution.

    A typical income level required per person in a developing country can be seen in the example of Afghanistan. Afghanistan’s development needs are based on the need for water, soil, housing, electricity, transport, schools and hospitals. The land area available for forest, agro forest and grassland development determines the extent of sequestration activity that the country can undertake. [This key variable has been examined for each developing country and a suitable development cost was calculated on a per capita basis and Afghanistan is given as an example here].

    The price of permits is determined on the basis of these development costs.

    Afghanistan will have 50 million people in 2030. Since 1990 it has lost 34% of its forests with the per capita forest cover reduced to 1.73 ha. It has 15 hectares of arable land per person, 0.26 hectares of permanent crops and 60 hectares of grasslands. At the present level of agricultural production there will only be ¼ kilogram of cereal production per person per day in 2030. The country has no global warming pollution. The required infrastructure in Afghanistan is:
    1) 10 million new net zero energy and net zero global warming pollution homes, each measuring 1000 square foot, and available at a cost of 100 UK Pounds per square foot. This cost includes the net zero energy solution for the homes.
    2) 1 kW additional renewable electrical capacity per person for irrigation and other productive uses, including plug-in electric vehicles. The chosen renewable energy form is biomass pellets made from biomass grown on 60 ha of grasslands per person. This is more than enough land per person to produce the required 10 tonnes biomass per person to give each person 1 kWh / hour for 20 hours every day. 10 hours of this can be used for charging the electric vehicle. The cost per person for 1 kW installed biomass capacity including grassland development cost and transmission and distribution lines is 5’000 Pounds kW.
    3) The cost of electric cars is 10’000 pounds per car, and 1000 pounds per year for new batteries. 1 million electric vehicles are needed.
    4) 50’000 schools and 50’000 hospitals at a cost of 100 pounds per square foot, each 5000 square foot.
    5) Clean water costs 1000 pounds per person
    6) 1 ha soil conservation and restoration of agricultural land costs 1000 pounds per person
    7) 1 ha forest conservation costs 5000 pounds per person.

    Thus Afghanistan needs 33’800 pounds Sterling per person from its share of permits to be sold to developed countries to cover its development needs.

    Having examine all other developing countries’ land availability and investment needs, we fix a cost of 35’000 pounds per person to transform developing countries into net zero global warming pollution and net zero energy life-style countries. The price of 1 permit is thus 1182 pounds per tonne of carbon dioxide equivalent.

    For the period 2010 to 2030 there will be 210 billion permits available globally, starting with 20 billion permits in 2010 and coming down by 1 billion every year to 0 in 2030. The permits will be allocated to the developing countries on the basis of population. The total population of the developing countries is 7’093’080’000 people. There is no space here or on ly blog to give the table with the number of permits for sale for each developing country but it is available if you want it. It gives the permits as as the percentage of the total for each country and the total number of permits (each permit is 1 tCO2e).


  2. Global Warming and Climate Change is the biggest environmental issue that we face these days. the long term effects of these environmental changes to a nations economy is quite damaging. there would be a shortage in food supply as well as on water supply too.


  3. Tom Wigley has an interesting guest post at BraveNewClimate on the effect of curring CO2 emissions to zero by 2050 at http://bravenewclimate.com/2010/11/24/effect-zero-co2-2050/

    It draws upon the following article:

    T. M. L. Wigley, L. E. Clarke, J. A. Edmonds, H. D. Jacoby, S. Paltsev, H. Pitcher, J. M. Reilly, R. Richels, M. C. Sarofim and S. J. Smith (2009) Uncertainties in climate stabilization. Climatic Change 97, 85-121, DOI: 10.1007/s10584-009-9585-3, available at http://www.springerlink.com/content/l96x6713hk17l062/


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