North East Brazils Drought

Droughts

While Climate Change has increased precipitation in some places- as seen in last week's post, other regions have seen drying trend contributing to drought (Trenberth, 2007). Droughts are not only caused by lack of rainfall, but also increased evaporation from soil and vegetation, associated with warming (Dai, 2011).

There has been a global trend, that has seen an increase in drier, hotter areas and dry regions becoming drier, which can both be traced to human influence. The increase in GHG emissions have contributed significantly to this recent drying, by driving warming over the sea and land (Dai, 2011).

There is considerable disagreement about the concept of drought. In North East Brazil, based on rainfall records meteorologists, dispute some Brazilian scientists and policy makers claims to how long the region has been experiencing drought for (Wilhite, 2009).

Climate change and Drought- NE Brazil

A recent study published this year- 'Drought in NorthEast Brazil- past, present and future' suggests that the droughts which have traditionally affected this region are being worsened by the effects of climate change.

Droughts have been recorded in this region since the Portuguese Colonisation in the early C16th. However, the droughts are getting worse and scientists warn that this could lead to desertification of the region. The latest drought, which began in 2012, is the worst reported for over a century.

Figure 1: Rainfall anomaly (mm month^-1) during the peak rainy season (february- May) in Northeast Brazil from 1951- 2014

source:http://link.springer.com/article/10.1007/s00704-016-1840-8

ENSO does influence interannual variability in this region. However, of the most recent, only the droughts occurring in 1998, 2002 and 2012 occurred during ENSO years (Figure 1).

This region covers 18% of Brazil's total area and is home to 53 million people. With 34 inhabitants per sq mile, it is the most densely populated semi- arid region in the world. The combination of lower- than- average rainfall and land-use changes due to rapid population growth and increase in economic activity, are exacerbating the impacts of drought.

What does the future hold?

Future climate projections show temperature increases, rainfall reductions, and an increase in the tendency for drought and aridification in this region.

This report's analysis of rainfall, temperature, and dry spell anomalies, confirmed the IPCC (2014) projections of increases in the severity and duration of droughts by late c21st, but low confidence for the first half of the century (Figure 2).

figure 2: Past and Projected temperature and precipitation change 

Source: https://www.ipcc.ch/report/ar5/syr/

The author says

 "Climate change will extract a heavy price from the northeast. Is it inevitable? Today there is only one certainty. In the future, there will be longer and hotter drought periods."

"Climate projections generated by the climate model suggest that from now on, more severe and prolonged droughts will be the rule, not the exception."

The projected future in NE Brazil of increasing frequency and length of dry spells, and droughts, has created much concern among natural resource managers, farmers, development specialists, researchers, and policymakers.  Water security, Food security, and Energy security, are at further risk due to these changes, which will in turn affect the sustainable development of this region.

This report references (Wilhite, 2014), that the current drought in NE Brazil has:

"Sparked a new round of discussions on improving drought policy and resilience to drought, as well as management at the federal and state levels in the region"

However, it is argued by Jan Rocha:

"The alarming but very possible scenario is almost completely ignored by politicians, who over the decades have used the droughts to further their own careers."

Concluding thoughts

Although drought and aridification on their own do not cause land degradation, they can make the land more vulnerable to human- induced degradation. Therefore, if not already, climate change will become the biggest challenge for North East Brazil, intensifying this environmental phenomenon. Therefore a number of obstacles will need to be identified and dealt with through appropriate policies, in order to reduce the risk for local people.