There is now sufficient data to say that the earth’s climate is changing, and that human use of coal, oil, and natural gas is the primary cause of our warming world. Last week, the UN Intergovernmental Panel on Climate Change (IPCC) released the second section of their fifth assessment of the globe’s climate. How does this report compare to the last report, released in 2007? Let’s start with what has stayed the same: climate scientists continue to view the situation as extremely serious.

So what’s changed? This report focuses on the impacts of climate change, how we can adapt to it, and who it will affect most. It has highlighted the stark fact that developing societies and poorer populations are the most vulnerable to the impacts of climate change. As the earth’s temperature rises, some regions experience more evaporation of water resources and get less rainfall. However, the same temperature increase that leads to drought in some areas leads to heavier than normal precipitation and flooding in others. Climate scientists predict which regions will be subject to such changes using computer simulations of atmospheric circulation patterns and hydrologic data (like stream flows, soil moisture, and precipitation).

Poorer societies have fewer resources and lower quality infrastructure to buffer them from the effects of drought and floods.  They are also vulnerable to high prices of food as crop production becomes more threatened in a warming world. There are short-term gains from crops doing well in previously too-cold higher latitudes, but as the earth as a whole warms any increase in higher latitude crops will decline.

Cities are adapting to climate change by protecting infrastructure that is most critical to recovering after a disaster. New York City, in the wake of Hurricane Sandy, has already started focusing on “climate-proofing” its electrical system and has just unveiled a comprehensive $17billion plan to protect and transform New York’s infrastructure with extreme weather readiness in mind. Among many other fixes, the “climate-change-readiness” plan includes building new flood control infrastructure for coastlines and electrical systems.

 A special thanks to Harvard Ph.D student Archana Dayalu for sharing her expertise on the subject and to Marc Presler for sharing his editorial skills.

Managing editor on this piece was Amy Gilson.

Link to the IPCC report: http://www.ipcc.ch/

Read more from SITN about climate this July in a special edition of Signal to Noise and more from Archana in her Signal to Noise piece here: http://sitn.hms.harvard.edu/flash/2012/why-sustainable/

Further reading and watching from SITN:

SITN lecture on Extreme Weather: Causes, Effects, and connections with Climate: http://sitn.hms.harvard.edu/seminars/2013/extreme-weather-causes-effects-and-connections-with-climate/

Agriculture and drought in Africa: http://sitn.hms.harvard.edu/flash/2011/issue94/

Further reading:

http://www.realclimate.org/index.php/archives/2014/04/impacts-of-climate-change-part-2-of-the-new-ipcc-report-has-been-approved/

http://www.nytimes.com/2014/04/01/science/earth/climate.html?ref=science&_r=3

https://www-pls.llnl.gov/?url=science_and_technology-earth_sciences-agriculture

http://www.newyorker.com/reporting/2013/01/07/130107fa_fact_klinenberg)

https://www.governor.ny.gov/press/01072013-cuomo-biden-future-recovery-efforts

Image:
http://www.ipcc-wg2.gov/images/books/AR5cover1.jpg