India's Climate Prediction in 2030 and Manipur
- Part 2

N Munal Meitei *

Key results of 4X4 Assessment for 2030s and Manipur

Climatologically, the entire Indian region is divided into the Western Himalayas, North-west, North-east, Northern-central region, Eastern coast, Western coast, and the interior Plateau. The projected climate change information obtained from PRECIS driven by IPCC A1B scenario for these regional entities has been adapted for the present assessment as per the regions in focus.

For example, the projections for the Western Ghats refer to projections for the western coast. Projections for the coastal region represent the climate projections for the western coast and the eastern coast together. Projections for the Himalayan region represent climate of the Western Himalayas and projections for the North- Eastern region represent the climatological entity of the North-east including Manipur.

1. Temperature

PRECIS simulations for the 2030s indicate an all-round warming over the Indian subcontinent associated with increasing GHG concentrations. The annual mean surface air temperature is projected to rise by 1.7°C and 2.0°C in 2030s. Seasons may be warmer by around 2.0°C towards the 2030s. The variability of seasonal mean temperature may be more in winter months. In Manipur the mean annual temperature is projected to rise by 25.8±0.8oC to 26.8±0.9oC in the 2030s. The rise in temperature with respect to 1970s ranges from 1.8°C to 2.1°C.

2. Precipitation

All the regions under consideration show a small increase in annual precipitation in the 2030s with respect to the baseline, that is 1970s. For Manipur, the average mean annual rainfall is projected to vary from a minimum of 940±149 mm to a maximum of 1330±174.5mm. The increase in the 2030s, with respect to the 1970s, is of the order of 0.3% to 3%.

3. Extreme temperatures

The analysis of the model runs indicate that both the daily extremes in surface air temperature, that is, daily maximum and daily minimum may intensify in the 2030s. The spatial pattern of the change in the lowest daily minimum and highest maximum temperature suggests a warming of 1.0°C to 4.0°C towards the 2030s. In North-Eastern region including Manipur, the minimum temperatures are likely to rise from 1.0°C to 2.5°C and maximum temperatures may rise by 1.0°C to 3.5°C.

4. Extreme precipitation

Extreme precipitation can be defined in terms of number of rainy days if it exceeds the currently observed average number of rainy days in a year (exceeding 2.5mm) as well as the volume of rainfall in a day if it exceeds a particular threshold. Currently, the frequency of rainy days is more in East and North-East India and less over western India.

The intensity of rainy days increases in a more warming scenario. In Manipur, the number of rainy days is likely to decrease by 1–10 days. The intensity of rainfall in the region is likely to increase by 1–6mm/day

5. Cyclones

Since 1986, a decreasing frequency in cyclones along the Eastern coast surrounded by the Bay of Bengal and the Northern Indian Ocean has been observed. The projected number of cyclonic disturbances along both the coasts in the 2030s is estimated to decrease with respect to the 1970s. However, cyclonic systems might be more intense in the future. For our State, we may get more intense cyclone in future.

6. Impacts on agriculture

Rice : Irrigated rice yields in Manipur may range between -10% and 5%, with respect to the 1970s, while the rain-fed rice yield may vary between–35% to 5% with respect to 1970s.

Maize : Maize crop yields of the State are projected to reduce by about 40%.

Livestock productivity : The Temperature Humidity Index (THI), an index used to define losses due to thermal stress is highest in the months of April–October with THI > 80 and is likely to remain under highly stressful conditions in 2030s reducing the milk productivity

Orange, Mango and Lemon etc.: The production these fruits in our State may decrease as increase in maximum temperature which led to a reduction in total cold season in the region. With increasing temperatures, it is anticipated that there may be an all-round decrease in fruit production and the line of production may shift to higher altitudes.

7. Natural ecosystems and Biodiversity

It has been concluded that the forest vegetation type of the four eco-sensitive regions are vulnerable to projected climate change in the short term, that is, in 2030s, even under a moderate climate change scenario (A1B). The impacts vary from region to region. In North-Eastern region including Manipur which has much of the dense forests in this region are the part of the Himalayan biodiversity hotspot. In this region, only about 8% of the 73 forested grids are projected to undergo change in the 2030s. The region is projected to see an increase of 23% in NPP (Net Primary Productivity) on an average.

8. Impact on Human Health

A qualitative assessment indicates that morbidity and mortality of the population in the regions under focus are likely to increase with warming temperatures and variable precipitation as they have direct as well as indirect effects. Direct effects can manifest as heat stress and indirect effects can be in terms of vector borne diseases, water borne diseases and malnutrition etc.

A quantitative assessment has been carried out for determining the transmission of malaria in the 2030s. The transmission windows have been determined in terms of (a) temperature as well as (b) temperature and relative humidity requirements for transmission. Even if the required humidity is not existing in the atmosphere the mosquito vectors seek microniche for their resting to get the required RH for survival.

The reason of almost similar projections in North-Eastern states may be due to prevalent high RH. The fate of the Manipur including the North-Eastern region in the year 2030s is a likelihood that the windows of transmission of malaria may increasingly remain open for at least 7–9 months and may even remain open for a larger number of months (10–12 months) in a year.

9. Water

The water resources in this study have been assessed in terms of water yield in the various river basins that are part of these regions. The water yield is the total surface runoff, which is usually a function of the precipitation, its distribution, evapotranspiration (ET) and soil characteristics. The water yield in the North-Eastern region including Manipur exhibits considerable spatial variability in the 2030s but is in line with the projected patterns of precipitation and evapotranspiration.

The northern parts of the North-East in the 2030s, with respect to 1970s, show a reduction in precipitation by 12%. The central portion of the North-eastern region shows an increase in precipitation by 0% to 25%. However, the majority of the North-Eastern region except for Mizoram, Tripura, Manipur and Assam shows an increase in the evapotranspiration in the 2030s. The increase in the water yield in Assam and Manipur is projected to increase by 40%.

10. Impact of Climate change on frequency of Droughts

The percentage change in the spatial distribution of Soil Moisture Deficit Index (SMDI) between the 1970s and 2030s has been used for defining the drought index. The weeks when the soil moisture deficit may start drought development (drought index value between 0 and -1) as well as the areas which may fall under moderate to extreme drought conditions (drought index value between -1 and -4) have been assessed.

There is an increase in the drought development for those areas of various regions that have either projected decrease in precipitation or have enhanced level of evapotranspiration in the 2030s. Similarly, the weeks belonging to moderate soil moisture stress show an increase in severity of drought from baseline to the mid-century scenario, which is self-evident. It is very evident from the depiction that the moderate to extreme drought severity has been pronounced for this Region where the increase is more than 20% in many areas despite the overall increase in precipitation.

11. Impacts of climate change on floods

Possible floods have been projected using the daily outflow discharge in each sub-basin as generated by the SWAT model, ascertaining the change in magnitude of flood peaks above 99th percentile flow in 1970s and in 2030s. Change in peak discharge equal to or exceeding at 1% frequency in the 1970s and 2030s for various regions indicates that the flooding varies from 10% to over 30% of the existing magnitudes in most of the regions. This has a very severe implication for existing infrastructure such as dams, bridges, roads, etc., in the areas and will require appropriate adaptation measures to be taken up.

What is our responsibility?

In the industrialized countries, due to technological advancement, they have developed high cost infrastructures to meet the challenges from Climate Change at their country level. But in our country like India due to its prohibitive cost, we are not able to install those technologies. Therefore to face the challenges of Climate Change in the years to come, the best option that we can effort is to plant more trees wherever it is possible. A tree in its life can sequestrate about one ton of Carbon dioxide and gives away the required oxygen for 10 peoples in a year.

Henceforth, for a clean future Environment, it is pertinent to plant more trees not only to save our wealth of the country, the Forests but for the future generation to come. To save our valued Forests, unless the acceptance from all sections of the society that we will be in an Environmental turmoil and facing from various climatic challenges by 2030, the law alone cannot be able to save our Forest. Therefore, it is our shoulder responsibility to save our dwindling Forest right now.

Let us save Forest and Plant more trees for a bright and prosperous future

Concluded ...