Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 7:10 PM GMT on April 13, 2014
Climate change is a huge threat to civilization if we do nothing more to reduce it, but the costs are very affordable if we start now, said the Nobel-prize winning Intergovernmental Panel on Climate Change (IPCC) today, in the third installment of their once-every-seven-years report on the climate. Today's report on mitigation--how we can slow down climate change--was the most hopeful of the reports, since it found that the cost of keeping global warming under the "dangerous" level of 2°C will only reduce "consumption growth" of the global economy by 0.06% per year if we start immediately and act strongly. Since consumption growth is expected to increase between 1.6% and 3% per year in the coming decades, we’re talking about annual growth that is, for example, 2% rather than 2.06%. This is a small price to pay to greatly decrease the risks of increased hunger, thirst, disease, refugees, and war outlined in the IPCC's frightening Working Group 2 report on risks and adaptation released two weeks ago. Today's report was authored by 235 scientists from 58 countries, and was approved by the governments of every nation of the world who cared to send a representative to the week-long approval meeting in Berlin, Germany. There is one more portion of the 2013 - 2014 IPCC report coming, a grand summary of Parts 1, 2, and 3 that will be released around November 1, 2014. Some key themes from today's report on mitigation:
Emissions of greenhouse gases are rising at a near-record pace. Greenhouse gas emissions grew 2.2% per year between 2000 - 2010, compared to a rate of 1.3% per year between 1979 - 2000. The increase was 3% per year between 2010 - 2011, and 1 - 2% from 2011 - 2012. About 76% of the greenhouse gases emitted were in the form of CO2, with 16% from methane. In 2010, ten countries accounted for about 70% of the world's CO2 emissions from fossil fuels and industrial processes. About half of the cumulative human-caused CO2 emissions between 1750 and 2010 have occurred in the last 40 years.
If we are going to avoid a dangerous 2°C (3.6°F) warming, we must make large and rapid cuts in greenhouse gas emissions. At the 2010 climate talks in Cancun, the governments of the world agreed that global warming should be kept under 2°C (3.6°F) above pre-industrial levels in order to avoid a "dangerous" threshold of climate change. The new IPCC report says that in order to do this, the share of zero and low carbon energy sources like solar, wind, nuclear, and unproven technologies like fossil fuel with Carbon Capture and Storage (CCS) must at least triple by 2050, and greenhouse gas emissions will have to fall 40 - 70%, compared to 2010 levels. By 2100, emissions of CO2 need to be near zero. This would require about $30 billion per year less to be spent on fossil fuels from 2010 - 2029, $147 billion per year more to be spent on zero and low carbon energy sources, and several hundred billion per year more per year to be spent on energy efficiency. (For comparison, the annual global total investment in the energy system is $1.2 trillion.) The report emphasizes that the greenhouse gas reduction promises made at the 2010 Cancun summit for the year 2020 are not enough to keep warming of the planet below 2°C at the lowest cost, though will likely keep a 3°C temperature rise from occurring.
If the world delays mitigation through 2030, it will be much more expensive and perhaps impossible to keep warming below 2° C. Models that delayed doing significant emission cuts until 2030 showed that the economic costs during the transition to renewable energy and in the long-term would be higher. Also, if some key (and unproven) technologies such as Carbon Capture and Storage (CCS) and Bio-Energy with Carbon Capture and Storage (BECCS) turn out not to be feasible at large scales, it will be difficult to keep warming below 2° C.
Keeping Earth's temperature rise below 2°C will have additional co-benefits. For example:
1) Reducing air pollution. The World Health Organization reported that in 2012 about 7 million people died--one in eight of total global deaths--as a result of air pollution exposure.
2) Improving energy security, leading to less price volatility and fewer supply disruptions.
3) Environmental protection.
There is a huge opportunity in the next few decades to build low-emission cities. Urban land cover is projected to expand by 56 - 310% between 2000 and 2030. Most of this urban infrastructure has yet to be built, presenting a tremendous opportunity to build the new urban areas so they emit fewer greenhouse gases. However, this will require strong policy, technical, financial and institutional measures.
Economic and population growth are the main drivers of greenhouse gas emissions. We've grown far more efficient at producing goods using less energy, meaning that the "energy intensity" of the global economy steadily declined from 2000 - 2010. However, increasing economic growth and population growth have outpaced the decline in energy intensity, resulting in higher greenhouse gas emissions. "Without additional efforts to reduce GHG emissions beyond those in place today, emissions growth is expected to persist driven by growth in global population and economic activities." If we take no additional measures to slow down human-caused climate change, the planet is expected to warm by about 4°C by 2100 compared to per-industrial levels. That's the same difference in temperature as between today's climate and the Ice Age.
Greenhouse gas emissions from deforestation are decreasing. Some good news is that the global rate of deforestation has been going down, which has made greenhouse gas emissions due to land use changes decline (greenhouse gas emissions due from agriculture, forestry, and other land use are 24% of the human total.) These type of emissions are projected to continue to fall, and possibly go to zero by 2100.
Renewable energy is growing fast, but needs help to increase its market share. In order to help renewable energy grow more rapidly, direct or indirect subsidies are needed. Indirect subsidies could occur by taxing fossil fuels or adopting a cap and trade system. The report doesn't recommend any particular policy actions, but does note that "to help reduce possible adverse effects on lower income groups who often spend a large fraction of their income on energy services, many governments have utilized lump‐sum cash transfers or other mechanisms targeted on the poor."
New Blockbuster IPCC Climate Report: Comprehensive, Authoritative, Conservative, my September 2013 post on who the IPCC is, and how they write their reports.
Landmark 2013 IPCC Report: 95% Chance Most of Global Warming is Human-Caused, my September 2013 post on Part I of the 2013 - 2014 IPCC report.
IPCC: Climate Change Increasing Risk of Hunger, Thirst, Disease, Refugees, and War, my March 31, 2014 post on Part II of the 2013 - 2014 IPCC report.
Available: professionals willing to speak about climate change to local groups
If your school, chamber of commerce, church, library, or community club needs a local expert on climate science to come speak, the University Corporation for Atmospheric Research (UCAR) and the United Nations Foundation can help out, thanks to a new effort called climatevoices.org. The organization has more than 160 volunteer experts from al 50 states in a database that is searchable by geographic location, expertise, and languages spoken. If you are have expertise in climate science and are interested in volunteering for this network, please go to climatevoices.org and create a profile. I have my own set of slides I use for such talks that anyone is welcome to borrow from, available at http://www.wunderground.com/hurricane/2013/climatetalk.ppt.
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