Avoiding dangerous climate change

Global mean surface temperature change from 1880 to 2015, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean. Source: NASA GISS.

"Avoiding dangerous climate change" (or "preventing dangerous anthropogenic interference with the climate system") is both a major, explicit policy of many national governments regarding global infrastructure development, harmonized with climate action, and a major objective and focus of current, related scientific research.

International policy

The IPCC Second Assessment Report (1995) published by the International Panel on Climate Change, stated as objective:[1]

"The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner." (Emph. added)

In 2002, the United Nations Framework Convention on Climate Change (UNFCCC),[2] an international organization established by treaty in 1992, incorporated the objective as the focus of its formal Framework Convention policy.[3]

Avoiding dangerous climate change and its equivalent terms have continued in common usage in the policy community,[4][5] scientific literature.[6][7] and news media.[8][9][10] The problem that arises is to decide what level of interference would lead to "dangerous" change.[11] The relevance of the issue is increasing as existing Earth System Models project that as early as 2020 in tropical areas, 2047 on average globally, the Earth's surface temperature could move beyond historical analogs, potentially impacting over 3 billion people and the most diverse places on Earth.[12]

The current international agreement toward avoiding dangerous climate change was made at the 21st Conference of Parties (COP 21), in Paris in December 2015. It reaffirms the goal of "holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels."[13] However, the agreement is aspirational and non-binding.[14]

How much global temperature rise is dangerous?

Limiting the average global surface temperature increase of 2 °C (3.6 °F) over the pre-industrial average has since the 1990s, been commonly regarded as an adequate means of avoiding dangerous climate change, in science and policy making.[15][16] In 2005 an international conference called "Avoiding Dangerous Climate Change: A Scientific Symposium on Stabilisation of Greenhouse Gases"[17] examined the link between atmospheric greenhouse gas concentration, and the 2 °C (3.6 °F) ceiling on global warming thought necessary to avoid the most serious effects of global warming.[18] Proceedings of the symposium were published in 2011, in an open-access special issue of the Royal Society's Philosophical Transactions A.[19]

However, recent science has shown that the weather, environmental and social impacts of a 2 °C rise would be much greater than the earlier science indicated, and that impacts of a 1 °C rise are now expected to be as great as those previously assumed for a 2 °C rise.[11] In a July 2011 speech, climate scientist Kevin Anderson explained that for this reason, avoiding a dangerous climate in the conventional sense is no longer possible, because the temperature rise is already close to 1 °C.[20][21]

Moreover, Anderson's presentation demonstrates reasons why a temperature rise of 4 °C by 2060 is a likely outcome, given the record to date of action on climate, economic realities, and short window of time remaining for limiting the average surface temperature rise to 2 °C or even 3 °C.[20] He also states that a 4 °C rise would likely be an unstable state, leading to further increases in following decades regardless of mitigation measures that may be taken.[20] The consequences of failing to avoid dangerous climate change have been explored in two scientific conferences: the 4 Degrees and Beyond International Climate Conference held at Oxford University in 2009; and the Four Degrees Or More? Australia in a Hot World held at the University of Melbourne in July 2011.

Some expressions of dangerous climate change

Dangerous effects of global warming on human health could manifest. Increased storm surges from sea level rise could inundate homes and infrastructure, or cause crop damage.[22] With the increase of water vapor, or ocean current changes due to melt water, extreme weather patterns can further develop (wind speeds, wave action, or stronger storms).[23] Some of the possible changes are irreversible on the human timescale, such as loss of the ice sheets. Due to a positive feedback, depending on mass balance and glacier's grounding lines, several glaciers in Antarctica have been identified by NASA researchers to be already in irreversible decline.[24] Mass migrations and impacts on social stability, as well as abrupt climate changes are also a concern.[22]

See also

References

  1. ↑ IPCC 1995. Second Assessment Report: Climate change 1995, commonly known as "Second Assessment Report" or "SAR".
  2. ↑ The Kyoto Protocol is a protocol to the UNFCCC.
  3. ↑ "United nations framework convention On climate change" (PDF). UNFCCC. 2002.
  4. ↑ IPCC 2001. Third Assessment Report: Climate change 2001.
  5. ↑ IPCC 2007. Fourth Assessment Report: Climate change 2007.
  6. ↑ Schneider, S. (2009). The worst-case scenario. Nature (458:7242, p.1104-1105).
  7. ↑ Lenton, T. (2011). 2 °C or not 2 °C? That is the climate question. Nature (473:7).
  8. ↑ UPI. 27 Oct. 2011. Review: Warming target needs action now
  9. ↑ Reuters. 23 May 2011. Climate change warnings add heat to Australia CO2 price.
  10. ↑ The Australian. 1 June 2011. Clash of cultures, economics and ideology
  11. 1 2 Smith, JB.; Schneider, SH.; Oppenheimer, M.;, Yohe, GW.; Hare, W.; Mastrandrea, MD.; Patwardhan, A.; Burton, I.; Corfee-Morlot, J.; Magadza, CH.; others (2009). "Assessing dangerous climate change through an update of the Intergovernmental Panel on Climate Change (IPCC) "reasons for concern"". Proceedings of the National Academy of Sciences 106 (11): 4133–7. doi:10.1073/pnas.0812355106. PMC 2648893. PMID 19251662.
  12. ↑ Mora, C (2013). "The projected timing of climate departure from recent variability". Nature 502: 183–187. doi:10.1038/nature12540.
  13. ↑ Agreement of the Parties, COP 21 Paris, 12 Dec. 2015.
  14. ↑ The Paris Agreement Does, and Doesn’t Do. 350.org, 12 Dec. 2015
  15. ↑ den Elzen M.; Meinshausen M. (2005). Netherlands Env. Assessment Agency. Meeting the EU 2°C climate target: global and regional emission implications.
  16. ↑ Rogelj, J.; Hare, B,; Nabel, J.; Macey, K.; Schaeffer, M.; Markmann, K.; Meinshausen, M. (2009). Halfway to Copenhagen, no way to 2°C. Nature Reports Climate Change.
  17. ↑ Conference website. Avoiding Dangerous Climate Change.
  18. ↑ Lazarus, M.; Kartha, S. 2009 (Oct.). Linking Technology Development with Emissions Commitments: Exploring Metrics for Effort and Outcome. Stockholm Environment Institute Working Paper WP-US-0909. (Original Report issued in April, 2007 for the French Environment and Energy Management Agency, ADEME.). See first page of the introduction, at p.13 of the pdf file.
  19. ↑ Society R. (2011). Theme Issue: "'Four degrees and beyond". Philosophical Transactions - A. 369:1934
  20. 1 2 3 Anderson, K. (2011). Multi-media presentation. Climate Change: Going beyond dangerous -- Brutal numbers, tenuous hope, or cognitive dissonance? July 2011.
  21. ↑ Anderson, K.; Bows, A. (2011). Beyond 'dangerous' climate change: emission scenarios for a new world. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences (369:1934, p.20-44).
  22. 1 2 Clark, P.U.; et al. (December 2008). "Executive Summary". Abrupt Climate Change. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Reston, Virginia, USA: U.S. Geological Survey., pp. 1–7. Report website
  23. ↑ J. Hansen, M. Sato, P. Hearty, R. Ruedy, M. Kelley, V. Masson-Delmotte, G. Russell, G. Tselioudis, J. Cao, E. Rignot, I. Velicogna, E. Kandiano, K. von Schuckmann, P. Kharecha, A. N. Legrande, M. Bauer, and K.-W. Lo (2015). "Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming is highly dangerous". doi:10.5194/acpd-15-20059-2015.
  24. ↑ "West antarctic glaciers in irreversible decline". NASA. 2014.

Further reading

External links

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