By Matt Burdett, 4 April 2018.
On this page, we look at the impacts of climate change on people and places, including health hazards, migration and ocean transport routes and with a special focus on melting glaciers, extreme weather and drought.
Climate and people
Much of the focus of concern over climate change is about the impacts on people. These include:
- Melting glaciers and the impact on rivers
- Extreme weather and the economic cost of disasters
- Drought and the impact on human welfare
The following issues are dealt with in detail on their own pages on this website. :
- Sea level rise causing coastal flooding and other problems, especially for small island states
- Health hazards, such as increasing temperatures causing the spread of tropical diseases
- Migration, such as from areas which are flooded by sea level rises or areas that experience desertification as a result of low rainfall
- Ocean transport routes, such as the ability to sail around the Arctic Ocean all year round
Societal impacts of melting ice: river flow
As glacial ice melts each year in the spring and summer, it flows into rivers. Some of these rivers are the source of water for millions of people. Northern India uses water from the Ganges for irrigation and drinking as well as industry and electricity generation. If the glaciers in the Himalayas melt entirely, the steady supply of water in India’s rivers could end.
Some previous estimates have suggested that the Himalayan glaciers could have entirely melted by 2035, but this is now believed to be inaccurate. More recent projections for a mid-range climate warming suggest between 2% increase and 29% loss of glacial ice, and by 2100 a loss of between 15% and 78% (IPCC, 2014).
- Percentage change of mean annual streamflow for a global mean temperature rise of 2°C above 1980–2010 (2.7°C above pre-industrial). Source: IPCC, 2014 (p242)
In the long term, this could mean rivers will dry out. But in the short and medium term, major rivers are likely to see an increase in their volume. This is because as the ice melts faster, it will add more water to the river. The map above shows the projected changes in river levels. Across India, levels are expected to increase. There could be problems with dam failure (as the dam collapses due to the weight of the water behind it) but the impact of rising river levels is very uncertain because it depends on how people respond.
Societal impacts of extreme weather events
An extreme weather event becomes a disaster when the population affected cannot respond adequately without outside help. For example, they might need medical help from international charities to treat wounded people, or money from the government to rebuild infrastructure like bridges. Worldwide, the number of deaths from disasters is going down but the number of people affected is going up.
- Deaths and disasters. Source: Economist, 2017.
Extreme weather – in its widest sense meaning climatological and meteorological (climate and weather – such as tropical storms and heatwaves) – already causes vastly more damage than geophysical disasters (such as earthquakes, landslides and volcanic eruptions) and hydrological disasters (such as flooding).
- The number of disasters by cause. Source: Economist, 2017.
- The impacts of disasters. The left bar in each pair shows the 2006-2015 yearly average. The right bar shows the 2016 level. Source: Guha-Sapir, Hoyois, Wallemacq and Below, 2016.
The expected increase in extreme weather events could bring major problems for societies and economies. Although the warning systems for extreme weather events are getting better, the increase in population means that more people will be affected. Many of these areas of population growth are in low and middle income countries that are also in vulnerable areas, such as South East Asia, East Asia and Central America.
Aside from the numbers of people affected and killed, a common measurement of the impact of extreme weather is the economic cost. High profile disasters such as Hurricane Katrina (2005) and Hurricane Sandy (2012) cost billions of dollars of damage, and also in lost revenue – Sandy forced the closure of east coast ports resulting in losses to the overall economy of over US$50 billion.
The map below shows the ‘billion dollar disasters’ that occurred in the USA in 2017. Together, these disasters caused greater economic loss than in any year before, with over US$300 billion of damage.
- Billion-dollar disasters in the USA in 2017. Source: NOAA, 2018.
Using the billion-dollar measurement to assess disasters is a simple and easy way to understand the relative cost of a single extreme weather event. However, it’s very misleading:
- Some disasters such as wildfires can be seen in isolation, or as part of a general problem. Should we count each individual fire, or are all the fires in a region counted as one?
- It’s very hard to measure the true cost, especially for how much money is lost to the economy.
- Disasters that hit more wealthy regions appear worse than disasters that hit poorer regions, but the overall impact might be the other way round. A wealthy area can pay to rebuild, but a poor area will have lost a greater proportion of its wealth.
- It is very difficult to compare different countries because currency exchange rates vary.
- This metric is really only used in the USA. It’s very hard to find information about global billion dollar events.
Societal impacts of drought
The impact of drought are, tragically, too easy to see in the news today. A major effect in poorer countries is a loss of agricultural production and therefore a shortage of food. An extreme shortage of food is called a famine, but the definition is a bit more complex than than simply a lack of food – it also includes the number of deaths and the number of people affected. In the period 2010-2018, there were only two official famines, both in the Horn of Africa. The 2011 famine is documented here. Climate change is considered a major contributor to this food shortage as it has affected the rainfall which now comes less often and with less intensity (Oxfam, 2017).
Economist, 2017. Weather-related disasters are increasing. https://www.economist.com/blogs/graphicdetail/2017/08/daily-chart-19 Accessed 4 April 2018.
Guha-Sapir, Hoyois, Wallemacq and Below, 2016. Annual Disaster Statistical Review 2016. http://www.emdat.be/publications Accessed 4 April 2018.
IPCC [Intergovernmental Panel on Climate Change], 2014. Fifth Assessment Report. https://www.ipcc.ch/pdf/assessment-report/ar5/wg2/WGIIAR5-Chap3_FINAL.pdf via https://www.ipcc.ch/report/ar5/wg2/ Accessed 4 April 2018.
NOAA, 2018. NOAA National Centers for Environmental Information (NCEI), 2018. U.S. Billion-Dollar Weather and Climate Disasters. https://www.ncdc.noaa.gov/billions/ Accessed 4 April 2018.
Oxfam, 2017. Oxfam Media Briefing: A Climate In Crisis – How Climate Change Is Making Drought And Humanitarian Disaster Worse In East Africa. https://www.oxfam.org/sites/www.oxfam.org/files/mb-climate-crisis-east-africa-drought-270417-en.pdf Accessed 4 April 2018.
Societal impacts of climate change: Learning activities
- Create a spider diagram showing possible impacts of climate change on humans. 
- Create a table as shown below, and fill in each box. For each box there are two marks.
Climate change issue
Which do you think is the most serious impact? Write to your government representative to inform them of the issue and what should be done about it. Consider:
- Scale – do you want local, regional, national or international responses?
- Limitations – what currently stopping adequate action being taken about it, and what can you do to reduce these limitations?
- Evidence – use specific factual detail where possible
- Language – be persuasive!