Hot-spots & recent change

Identification of climate change hot spots and risks in specific regions, particularly Minas Gerais

PS Baker

R Ruiz

Belo Horitonte, 9th September 2013

How do we know what is happening? At the farm/district level?

• We know the climate is changing globally

• But we don’t know how this is manifesting itself at the local level – there are major regional variations

• We have climate maps that project future climate change – global, regional, some for coffee – up to 2050, 2100

• These are important for strategic understandings

• At a local level however these are not enough for extensionists and the many farmers who are facing difficulties now

• It’s a problem for the c&c initiative, which is trying to identify and prioritize risks

• We cannot help all farmers everywhere prepare for all possible CC risks

• We have to focus

• To objectively quantify the present climate/weather situation locally as much as possible

How do we know what is happening? At the farm/district level?

Example: E Africa projected to get wetter

• IPCC 2007 Projections for 2080-2099

But in reality it has been getting drier (Funk et al USGS)

Future rainfall is especially a problem

• We know it will get warmer

• But precipitation is much less certain for any given locality

– Wetter?

– Drier?

– Both (at different times of the year or longer period)?

• Very difficult to approach farmers about future flood risks if their recent experience is drought

Dealing with uncertainty

• What we need are accurate indications of how things have been changing in the recent past

• We use this as a guide to the present and the near future (and compare it with models)

• There is no ideal solution, but we believe it to be the best strategy

• But we have a practical problem

User-friendly historical weather data is mostly lacking!

• We need easy to understand maps that show coffee-relevant met. data

– E.g. to indicate zones getting drier

– E.g. zones where maximum temperatures are getting higher

• This sort of data does not exist – it’s a major failing – agrometeorology is not user-friendly

• So we are having to do it ourselves

• I.e.: turning data into info & knowledge

So we commissioned a study Ramiro Ruiz (Uni Belo Horizonte)

• Meteorological data used from 79 stations and 264 rain gauge locations, from 1960 – 2011

• Quality control procedures included: – Screening to identify erroneous data (e.g. Tmin > Tmax,

negative precipitation, etc.).

– Identification of temperature outliers using standard deviation thresholds.

– Statistical gap-filling of missing temperature data

– Homogeneity tests to detect data incontinuities

So we commissioned a study Ramiro Ruiz (Uni Belo Horizonte)

• Minas Gerais Jan-Mar rainfall (mm)

• 1961-1980

Rain mm

So we commissioned some work Ramiro Ruiz (Uni Belo Horizonte)

• Minas Gerais Jan-Mar rainfall (mm)

• 1981 – 2011: Getting drier in NE of Minas

Rain mm

MG – temperature

• Mean max temp for Sep- Nov (a critical period for flowering (get increasing flower abortion > 32°C)

T mean max

MG – temperature rises

• Mean max temp for Sep- Nov (a critical period for flowering (get increasing abortion > 32C)

T mean max

MG – temperature rises

• Mean max temp for Sep- Nov (a critical period for flowering (get increasing abortion > 32C)

• Getting hotter in north MG

T mean max

1995 coffee production

2011

For the first time…

• We have a simple visual way of seeing recent CC – and we think this is the best way to orient adaptation options

T mean max

Absolute maximum temperatures (Tmax) Statistically significant increases over MG

• Significant positive trends for the annual count of days with Tmax greater than 32oC (SU32).

• Stations at the southern region had a 5.56 (± 2.9) days per decade increase

• Zona da Mata (2.35 ± 1.8 days per decade ) at Caratinga and Viçosa). Filled triangle = significant

increase in Tmax

Daily temperature range Has been linked to coffee quality

• DTR = Monthly mean difference between Tmax and Tmin

• A mixed picture, but going up in Sul de Minas

Filled red triangles = significant increases

Signs of heavier rainfall events in parts of SW MG

• R50mm: annual count of days when precipitation greater than 50mm

Filled red triangles = significant increases

Annual water deficit in Minas Gerais 1960-1985 and 1986-2011 periods

1960 -1985

Annual water deficit in Minas Gerais 1960-1985 and 1986-2011 periods

1986 -2011

Mean annual water deficit by region in 1960-1985 and 1986-2011 periods

-40.4 mm -51.2 mm

-85.8 mm -103.1 mm

-183.5 mm -249.1 mm

-195.8 mm -270.5 mm

Summary

• This practical, user-friendly but science-based approach can give us some insight into local, recent climate change

• Especially where it coincides with model projections, it gives us considerable confidence to develop long-term strategies and help farmers make the right adaptation decisions (short to long term)

• We think this is the best way to guide us about what tools to use and where

• It is an approach that we would like to develop in all coffee-growing countries