Climate Change: Science and Impacts

1. Climate Change: Science and Impacts

2. In this module: • Why is the climate changing? • What are the impacts of climate change? • What does this mean for humanitarians? Photo: NASA

3. Climate Change

4. People report changes – and needs ”More and worse floods” ”Rains no longer normal – difficult to know when to plant” ”Our fields get eaten away by the sea” ”... so our children have to move away”

5. … and scientists’ data and observations confirm that the problems are global 1978 2002 Source: T. P. Barnett, J. C. Adam and D. P. Lettenmaier: Nature 438, 303-309 (17 November 2005)

6. Weather or climate? Will I need an umbrella today? Is it raining? What is the weather? I’m going to Nairobi in May – is that normally the rainy season there? What is the climate? Weather: Short Timescales “hours, days” Climate: Long Timescales “average over the past 30 years”

7. Mainfindings • Climate change is already happening • It is mostlycausedby man • It will continue • The rate of change is alarming • Extreme weather is getting more frequent • It is urgent to stop further warming IPCC – the ‘key reference’ on climate change IPCC Fifth Assessment Report, 2013

8. First question: Why is it getting warmer? Burning fossil fuels (e.g. coal, oil, natural gas) at unprecedented rates, sending “greenhouse gases” into the atmosphere Widespread deforestation (trees contain a lot of carbon, and when burnt CO2 is released ) Changing agricultural and land-use practices (agriculture releases other GHGs, CH4 and NO2) Answer: The rapid global warming of the past 100 years is caused mostly by human activity, mainly:

9. First question: Why is it getting warmer? Greenhouse gases are acting as a blanket around the earth

10. Rising temperatures, heat waves Sea level rise Melting ice Ocean acidification Changing rainfall patterns Changes in extreme events Second Question: Along with the GHG the earth is getting warmer – what does that mean? Scientists very sure Less clear, and regional differences

11. It’s getting hotter… Global temperatures are already rising

12. Warming will continue, but how much is our choice In the next few decades, temperatures will continue to rise, even if we almost completely stop emissions of GHGs today (blue line) This is because GHGs, especially CO2, stay in the atmosphere for a long time Therefore, we have further climate change “in the pipeline” because of the emissions already in the atmosphere

13. Warming will continue, but how much is our choice But if, and only if, we cut the global amount of GHG emissions quickly, we may avoid escalating warming in the second half of this century (the red line) If we act now to reduce global emissions, it is still possible to keep changes within a “manageable range” for our children

14. A 2012 World Bank report summarizes the potential effects of a 4°warmer world: it’s urgentto limit GHG emissions Scientist warnings are clear: We should avoid more than a 2°Celsius temperature rise in the coming century Themore we limit GHG emissions now, the less need for adaption to a future wilder weather

15. Rainfall is changing… Expected changein rainfall compared to NOW (1986-2005) Low scenario – if humans cause less climate change High scenario – if humans cause more climate change …but high uncertainties in many regions

16. New record highs Long term average Sri Lankan example: rainfall change

17. Third Question: What does climate change mean for the humanitarian sector? • Weather related disasters doubled over the past 2 decades • Increase in small- and medium-scale disasters Trends we have observed:

18. Risks = Hazards x Vulnerability x Exposure • The number of hazards is increasing • More people are exposed to extreme events • The vulnerability of people and assets is increasing = Risks are increasing

19. Projected changes in disaster patterns “A changing climate leads to changes in the frequency, intensity, spatial extent, duration, and timing of extreme weather and climate events, and can result in unprecedented extreme weather and climate events.” (IPCC, SREX, 2012)

20. Potential impact: Rising temperatures (source: NOAA-NCDC ) Heat waves: Rising temperatures lead not only to changes of average temperature but also to weather extremes. The increase of extreme weather-related disasters is particularly important for the Red Cross Red Crescent

21. Rainfall on very wet days NOW Potential impact: Changing rainfall patterns • Rainfall seasons around the world might shift  major implications for global agriculture • Amount of rainfall in each region might change • Number of extremely rainy events might increase in many places  changes in floods and water flows • Other places could see an increased number/duration of dry spells  water stress for vulnerable populations

22. Shift in seasonality as important as amount

23. Potential impact: Floods • Difficult to measure the frequency and intensity of floods, but generally there has been an increasing trend • Changes in rainfall patterns and precipitation intensity could put more people at risk from flooding Photo: IFRC, Pakistan floods 2010,

24. Potential impact: Coastal erosion, coastal flooding and salt water intrusion Photo: IFRC, Viet Nam coastal dike damages

25. Potential impact: Drought Photo: Jacob Dall

26. Possible impact: increasing food insecurity (Photo: Tamara Leigh/IFRC-Climate Centre)

27. Possible impact: Changing disease patterns (Photo: Nancy Okwengu/IFRC-Climate Centre)

28. Source: NASA – UNDP Potential impact: Melting ice 1978 2002 Source: Barnett et al. (2005)

29. Sea level rise NOW Potential impacts: Oceanic changes • Sea levels are rising – at a faster rate

30. ... and fish stocks decline, eroding livelihoods for millions of people Potential impacts: Oceanic changes Large scale degradation and/or loss of coastal and marine ecosystems • the oceans are becoming more acidic • sea surface temperatures are increasing Ocean acidification damages coral reefs – reducing their coastal protection effects

31. Potential impact: tropical cyclones impacts • Possibly an increase in the intensity of tropical cyclone activity (hurricanes/typhoons), coupled with higher storm surges due to sea level rise •  economic/human losses are expected to increase IFRC Source: NOAA

32. Climate risk assessments – check how our programming should be adjusted to meet new risk patterns • More and better disaster preparedness at all levels: Early warning – Early action plans with pre-determined actions triggered by information at different time scales • Up-scaling of climate-smart community risk reduction activities • More flexible, climate-smart health programming • Partnerships with weather agencies and technical specialists on adaptation options • Influence climate change policies RC action: Improve climate risk management In summary (more details in other CTK modules):

33. Geo-engineering: an emerging risk! UNEP 2009 – adapted from Lenton & Vaughan 2009

34. Humanitarian concern • Will vulnerable people worldwide have a voice in geoengineering decisions? • Will there be extra funding for humanitarian work in a geoengineered future?

35. THANK YOU! Further information: • ipcc.ch • climatecentre.org • ifrc.org