Decoding Goa's vulnerabilities to climate change
INTRODUCTION
From a climate change perspective, vulnerability refers to how a system copes with the adverse effects of climate change (CC). The world's coastal areas represent only 20% of the available land, but host more than half of the global population. These areas are already stressed by high levels of human activity, pollution, invasive species, storms etc., and CC is accentuating it all.
How Coastal Regions are vulnerable to CC?
Coastal development reduces the ability of natural systems to respond to climate change. Primarily, the impacts on coasts could be from: (i) Sea Level Rise (SLR); (ii) Warmer ocean temperatures; (iii) Changes in the frequency and intensity of storms and precipitation; (iv) Ocean Acidification. Some of the bio-geophysical impacts that may occur simultaneously and affect different sectors are shown in the table below.
THE GOAN CONTEXT
Excerpts from studies that highlight the impacts of climate change at local level in Goa are given below.
Coastal Erosion
Erosion is the physical movement of sediment away from the shore via wave and current action. Sea level rise has the capacity to intensify erosion. Goa has a shoreline of 151 km, of which, around 10.5 km was affected by erosion in 2006 (as per Kumar and team) that increased to 27.03 km in 2014 (as per Rajawat and team). While comparing the sediment transport rate, Kumar and team observed that net erosion is more at Colva, South Goa than Calangute, North Goa.
Impact of Infrastructure
A 2014 TERI study 'Climate Resilience Infrastructure Services'(CRIS) took stock, mapped Panaji's infrastructure (natural and man-made) and examined its vulnerability to SLR and extreme precipitation. Key outputs were: (i) Maps with hotspots/critical infrastructure; (ii) action plan to address climate criticality and; (iii) capacity building of the local government (City Corporation of Panjim and Town & Country Planning Department) for implementation.
Bleaching of Corals
Goa's coral reefs around Grande Island near Vasco support a large variety of marine species. Mr. P Kumar, a scientist at National Institute of Oceanography is studying the frequency at which the corals are being affected by warmer ocean temperature. According to him "Corals harbour colourful symbiotic algae. When the water gets too hot, the corals expel these algae and turn white, a process known as bleaching. If the water cools soon enough, the algae return. But prolonged bleaching can kill the corals". His study points out 20% decrease in algae in the Indian Ocean over the past six decades. Marine litter or the non-biodegradable garbage reaching our sea bed is also harming the marine life.
strong>Impact on Freshwater Resource
Since the impacts of CC differ spatially, region specific studies are required to scrutinize the changing rainfall patterns and its impact on river flow. To address this, TERI is currently conducting research (supported by DSTE, Goa) that couples future climate data with a hydrological model (SWAT) to predict the river flow at Uguem river sub-basin in South Goa. The findings of this study are expected by the end of this year.
Saltwater Intrusion in Groundwater
Excessive pumping of groundwater and SLR are the two main causes of saltwater intrusion. A 2015 study by Ms. Sujitha indicated the problem of saltwater intrusion in the wells of Baga and Nerul region (tourist belt of Goa) due to over pumping. In 2003, Dr. Chachadi showed that 0.5 m SLR can cause sea-water intrusion into the coastal aquifers of North Goa. Every square kilometre of area had 25 drinking water wells; therefore, even if 10 km2 of the coastal area gets affected by the 0.5m sea level rise, around 250 wells will have to be abandoned.
Solutions to tackle the impacts of climate change shall be discussed in the next part.
DID YOU KNOW?
• Ocean Acidification is caused by absorbing rising atmospheric carbon dioxide and thereby impacting marine ecosystems.
• Around 76% of India's coastline is prone to cyclones and tsunamis, while 59% of the country is vulnerable to earthquakes, 10% to floods and river erosion, and 68% to droughts.
• The Climate Change Vulnerability Index (CCVI) 2014 and the risk atlas prepared by Maplecroft, reveals that our neighbouring country Bangladesh is the most vulnerable country to climate change impacts in the world. India is at 20th position in the 'extreme risk' category.