Our Earth is warming, but why exactly should you care?
The summer of 2019 was full of weather records getting smashed. Heat waves struck many parts of Europe, South Asia and North America while forest fires rage in the summer of Australia now. Even far right parties in Europe want to protect the environment, while the conservative leaders elsewhere are refusing to act.
The reports released by the Intergovernmental Planet for Climate Change (IPCC) are clear: there is high confidence that the human-induced events are causing a major shift in the climate of the planet. We have already warmed the world by about 1 °C since pre-industrial levels.
This is attributed to massive changes in land use pattern around the world, the breakdown of natural systems that control temperature, and the release of greenhouse gases. With current trends in human activity, the temperature is expected to soar to 1.5 °C above pre-industrial levels between 2030 to 2050, depending on what action you and me choose to take now.
There is also a scientific consensus that this warming is ‘unusual’. Past climate changes did happen, but were completely different from this one — often part of natural cycles which reverted themselves. One feature of the present climate change is that it is happening too quickly, geologically speaking.
Given that the increase in temperature is happening, why should you worry about it? Here are nine ways in which a 1.5 °C warmer world will affect you — heat waves, cyclones, droughts, ice melting, ocean temperature change and acidification, water security, food security, air pollution and global migration.
#1 — An increase in the number of heat waves
The IPCC found that ‘one-quarter of the land has experienced an intensification of hot extremes (maximum temperature on the hottest day of the year) by more than 1°C and a reduction in the intensity of cold extremes by at least 2.5°C (minimum temperature on the coldest night of the year)’ due to warming. These extremes were understood to be out of natural variability. This could mean that India may face more deadly events of heat waves in future. Already, thousands of people were killed in the heatwaves of 2015, 2016 and 2019. Most regions in peninsular India had to bear the brunt, and you might have been part of it already.
Hot temperatures, failing monsoon, low water availability, changes in global or regional wind circulation may cause heat waves. The troubling aspect of a heatwave is that hot air removes moisture from the environment rapidly and increases humidity too. High humidity and high temperature for a prolonged time may be directly fatal for human beings (poor little animals suffer much more of course).
Heat waves can directly cause hyper-thermia and heat rashes in you. There are indirect threats too. A heat wave automatically demands you to use more water to cool down. In water stressed cities, which may experience drought like situation, this demand and supply gap may turn ugly.
If you use air conditioners and related devices to cool down, it demands a large amount of energy. This requires the local power supplier to burn more fossil fuels to get that energy, and the emissions cause further greenhouse effect and local heating.
The urban heat island effect, where cities are much warmer than the surrounding suburbs, will not help the situation. Fossil fuel based transport and cooling system exhaust adds to the misery.
#2 — Increased intensity of cyclones
IPCC assessed that ‘the global monsoon, aggregated over all monsoon systems, is likely to strengthen, with increases in its area and intensity, while the monsoon circulation weakens’. Changes in temperature distribution over land, and the chemical composition of air with addition of green house gases alters the global atmospheric circulation systems. Following extract sums up the science on this topic specific to India —
‘In the North Indian Ocean over the Arabian Sea, an increase in the frequency of extremely severe cyclonic storms has been reported and attributed to anthropogenic warming. However, to the east over the Bay of Bengal, tropical cyclones and severe tropical cyclones have exhibited decreasing trends over
the period 1961–2010, although the ratio between severe tropical cyclones and all tropical cyclones is increasing’…. ‘The observed increase in intensity of cyclones is more than what is predicted by the climate models.’
The science of attribution of climate change to particular weather events like floods and droughts is not yet fully developed, and hence every event must not be attributed to climate change quickly. But the consensus is that extreme weather events are more likely with global warming, even though their frequency remains the same. Cyclones like Vardha, Okhi, Gaja were unusually powerful in scale and impact, and in the near future a cyclone near you maybe helped by global warming.
#3 — Risks of drought
There is medium confidence that increased emissions and corresponding greenhouse effect contributes to soil dryness in many regions around the world. The argument cannot be over-stressed since enough data is not gathered everywhere in the world, mainly due to lack of support. Also, soil dryness by itself may not happen in very large scales.
The intensity of drought and water scarcity is amplified by other factors in the presence of global warming. Those factors may be — changes in land use patterns, deforestation, poor surface water management, excessive use for irrigation, and groundwater depletion.
Refer this for a short intro to droughts: https://pmdvod.nationalgeographic.com/NG_Video_DEV/951/427/droughts_480x360_464k.mp4
Increased temperature leads to more water removal from soil and from the surface water systems like rivers and lakes by the atmosphere. Groundwater depletion leads to increased dryness of the soil. Deforestation ensures that we no longer have the natural services of water capture, storage and recharge. Poor human management allows massive quantities of irrigation water to evaporate, and allows the remaining surface water to be polluted and unfit for use. Final nail in the coffin is hit by over-population, which leads to unrealistic aggregate demand for water at a time when temperature is increasing! Your very lifestyle aids global warming in causing droughts.
With drought conditions and a lack of forests to hold the soil in place, the process of desertification surely takes over soon.
#4— Meltdown of glaciers and ice sheets
The average temperature of the universe is close to 2.73 K while the earth has an average of 288 K. Have you wondered how earth maintains this temperature? It is done with the help of the massive heat gain from the earth’s interior and the sun’s radiation. The importance of sun’s radiation cannot be under-stated. Much depends on the thermal inertia of the atmosphere and the lithosphere to capture the heat. But now we are forcing earth to overdo it.
Do you think that changes in the Arctic have nothing to do with you? Think again. What happens in the polar regions today is an example of a negative feedback loop. It is best explained using the diagram below —
Global warming leads to melting of sea ice over time, especially in summer. The melting sea ice exposes the dark ocean water, which absorbs a lot of sun’s radiation and melts more ice. The cycle continues rapidly and ice retreats all around the world.
See the video here to get a perspective on the melting: http://fng-ads.fox.com/fw_ads/content/m/1/116450/52/5577780/Responsible20Tourism2030sec_1444573_435.mp4
Glaciers, ice sheets, ice shelves hold about 68% of the world’s freshwater and we have started letting it go into the oceans by our warming, losing an important source of water that might have otherwise resolved water conflicts. Glacial melt may sustain more livelihoods by providing more water to the plains below. For a period, agriculture may flourish. But you must remember that this melt is non-renewable. The ice that melts may have been there for thousands of years!
The ecosystem of the arctic and the antarctic probably suffers the most due to climate change. Animals like the polar bear, walrus, seals, penguins all depend on ice to varying degrees. The disappearance of ice causes direct harm. Furthermore, the increase in temperature in the mid-latitude sea causes many creatures to venture further north for survival. Plants, micro-organisms, animals in sea have very sensitive temperature preferences.
#5 — Ocean temperature change and Acidification
You may still wonder why an overall change of 1.5°C is making such a fuss in the scientific community. You need further perspective here. Since 1955, over 90% of all the global warming induced by humans is stored in the oceans as heat. This means that the atmosphere does not even bear the major brunt of our activities. The oceans are unimaginably huge, and yet we have managed to heat them up between 0.05°C and 0.11°C over the last 60 years.
Oceans act as the thermal reservoirs, and their ability to take up heat directly affects marine life and our sea-food industry. In an already stressed food security situation, you will not want to threaten our sea-food supply. There is also the problem of ocean circulation that is affected by changes in temperature. There is evidence for human induced temperature changes in specific regions of the sea, and we are inadvertently changing life giving and life saving ocean currents.
What happens to the carbon that we release to the atmosphere? The picture here tells the whole story.
Before human intervention, there existed a delicate and beautiful balance between plant world and the microbial world that decomposes and returns nutrients. This carbon cycle between the physical environment and the biosphere in oceans and land was sustainable. Human intervention added more carbon since 1850s and the oceans and the plants have taken up some of the ‘extra’ carbon as shown.
What people mean by carbon acceleration is this:
- We are constantly destroying the plant world (forests, grasslands, estuaries, swamps, etc) that is capable of removing carbon.
- We have heated the ocean which reduces carbon solubility (they can be stored easily in colder waters at high altitude). About 30% of all anthropogenic carbon is directly stored by oceans already, and we are stressing it out even more.
- The oceans are acidified and de-oxygenated by this additional carbon stored and that has again impacted marine life. This vital ecosystem is responsible for a major part of carbon recycling (see the figure!) and we are damaging it.
(see this video showing shocking destruction of corals with temperature: http://fng-ads.fox.com/fw_ads/content/m/1/116450/10/5472650/Pre_rollSouthAfricaTourismSEQ05_Final_TX_1413467_435.mp4).
#6 — Water security
It is clearly established that changes in temperature patterns across the world directly influence precipitation and the freshwater sources. Main global warming related problem for freshwater is the increased intensity of precipitation and droughts, with variations in frequency at many places. Precipitation is the most important method of freshwater replenishing itself, but we have erected many challenges for ourselves, here are four of them -
- Land use pattern has changed dramatically in the last 200 years. Agriculture comes under more area than ever, and it contributes significantly to green house gas emissions which furthers the intensity of extreme precipitation. Also, agriculture is very water intensive; most of the water simply evaporates.
- The surface water has been diverted too much to suit the needs of agriculture and industry, and less water remains for actual physical consumption. This obviously impacts all river ecosystems too.
- Deforestation is a problem for groundwater recharge and soil integrity.
- Groundwater over-exploitation to meet rising demands leads to decrease in water-table level. This leads to sea water incursion, which is emboldened by rising sea levels due to glacial melting! The resulting saltwater can no longer be fit for consumption.
#7 — Food security
The report by WHO on the state of the food security in the world says the following — ‘Hunger is significantly worse in countries with agricultural systems that are highly sensitive to rainfall and temperature variability and severe drought, and where the livelihood of a high proportion of the population depends on agriculture.’
Can you think of such a country? At a time when British kids learn to sing ‘Rain, rain go away’, Indian kids beg to differ. We are heavily dependent on the monsoon and we worship it.
Climate change clearly does these things: increases the intensity of storms and cyclones that destroy crops; increases the heat extremes that destroy crops; increases intensity and frequency of droughts that destroy crops; threatens water availability that destroys crops again. Of course, not all this happens always, but we are clearly able to see a trend of worsening.
Possible indirect effect: the already existing inequality is worsened by these ‘natural disasters’ and there ensues a lot of political and social struggle in the nation. It is useful to remember the recent news: the Global Hunger Index ranked India at 103 out of 119.
#8 — Air quality
The issue with air quality is related to the source of global warming — greenhouse gases. Carbon dioxide is the most famous of them all, but of course, there are other villains too. Much of the immediate emissions we encounter comes from the vehicles around us. Air pollution may be directly causing 4.2 million premature deaths worldwide per year.
Much of the menace we notice in India only in the time of winter, and this is because of the combined effect of high air pressure and complete withdrawal of monsoon currents. The low temperature, high pressure air allows the harmful gases to linger around us for longer. Also, as you would know by now from Delhi’s case, pollution does not always stay where it is created!
There is a separate emerging economy to cater to needs of air pollution. Probably more interest exists in making air purifiers than in stopping stubble burning. We have finally learnt to put a cost on the very air we breathe.
#9 — Global migrations
Perhaps the most threatening of all impacts is from migrations that result from flooding, droughts, sea level rise, heat wave, shoreline erosion and heat related incidents.
When environment pressures the rising population to move, the world leaders at present are getting more conservative and protective. What would the elaborate NRC exercise in Assam mean when the entire Bangladesh is called the most vulnerable country for flooding? Global conflicts related to environment may kill more people than actual physical harm and scarcity.
A supposedly positive note
If you observe carefully, the conclusions from the IPCC reports on individual issues about direct impact of warming which by itself is not very dangerous. All impacts are invariably magnified by other human activities or human induced changes. This is positive news because despite the projections of increase in warming, it shows that much of the impacts can be ‘managed’ by direct human intervention, if we choose to do it.
References:
- State of food security in the world report 2018, WHO
- Impacts of 1.5°C global warming on natural and human systems, IPCC
- Special report on Ocean and Cryosphere, IPCC
