Humboldt enigma and what does it mean for India (GS Paper 1, Geography)
Context:
- Humboldt suggested there was a relationship between temperature, altitude, and humidity on one hand and the occurrence patterns of species or their biodiversity on the other.
- His example of choice was the Chimborazo mountain in Ecuador, which has today become an important illustration of mountain diversity.
- Two centuries later, a group of biogeographers used modern tools to take another look at the drivers of biodiversity.
- Based on their findings, they proposed their own version of the link between biodiversity and mountains and called it Humboldt’s enigma.
Who was Humboldt?
- Alexander von Humboldt (1769-1859) was a polymath who recorded observations on various natural phenomena across the fields known today as geography, geology, meteorology, and biology.
- Once, when exploring South America, he recorded the distribution of plants on a mountain. He also noted how climates were similar across various mountains in different parts of the world but where specific features occurred on a mountain varied with elevation.
What is Humboldt’s enigma?
- The world’s tropical areas receive more energy from the Sun because of the earth’s angle of inclination. So the tropics have greater primary productivity, which then facilitates greater diversity: more ecological niches become available, creating more complex ecosystems and greater biological diversity.
- The proponents of Humboldt’s enigma have held that the earth’s tropical areas by themselves don’t contain all the biodiverse regions, that many areas outside the tropics are highly biodiverse. These places are mountains.
Humboldt’s enigma in India:
- A simple way to think of Humboldt’s enigma in India is to consider the biodiversity in our tropical areas, south of the Tropic of Cancer passing through Madhya Pradesh and Chhattisgarh. These areas are supposed to be the most diverse in the country. The Western Ghats plus Sri Lanka biodiversity hotspot lies in this zone.
- However, the eastern Himalaya are much more diverse. Some scientists have even suggested this part of the mountain range is the second-most diverse area of perching birds in the world. For river birds, the eastern Himalaya may be the most diverse.
Modern understanding of Humboldt’s enigma:
What drives biodiversity?
- The history of the earth, its geography, and the climate are the main drivers of mountain diversity. And different biodiversity at different locations is the result of changes in how these factors have intermingled over time and space.
- Mountains host two processes that generate biodiversity:
- Geological processes, like uplifts, result in new habitats where new species arise, so the habitats are ‘cradles’.
- Species on some climatologically stable mountains persist there for a long time, so these spots are ‘museums’ that accumulate many such species over time.
- Coastal tropical sky islands (mountains surrounded by lowlands), like the Shola Sky Islands in the Western Ghats, are a good example. Here, old lineages have persisted on the mountain tops as climates and habitats fluctuated around them in the lower elevations. This is the reason some of the oldest bird species in the Western Ghats, such as the Sholicola and the Montecincla, are housed on the Shola Sky Islands.
- Sometimes, the same mountain can be both cradle for some species and museum for others, depending on the species’ ecologies.
- The northern Andes range including Chimborazo is considered the most biodiverse place in the world.
Geology:
- Another critical force in biodiversity formation is geology. The foundations on which mountains are erected often differ from those on which low-elevation regions rest.
- Scientists have found that the more heterogeneous the geological composition of mountains is, the more biodiverse they are. Around the world, all mountains with high biodiversity have high geological heterogeneity as well, especially in the tropics.
- Even in tropical regions, some mountains with a lower variety of rocks are relatively less biodiverse.
- Plants are influenced by the type of soil, which depends on the type of rocks in that area. So high geological heterogeneity often produces unique habitat patches on mountains within similar climate regimes, and promotes diversification.
What drives biodiversity in the eastern Himalaya?
- Climate dissimilarity is still one crucial factor, something Humboldt also indicated based on his observations of the Chimborazo and understood to be a paradigm.
- Researchers have also found some groups of birds to have evolved elsewhere and dispersed to the Himalaya, resulting in higher diversity there.
Conclusion:
- Multiple factors drive diversification and the Humboldt’s enigma in different parts of the world. An important limitation of scientists’ attempts to explain biodiversity patterns is the lack of fine data on where species occur. For now, birds are the best-described group around the world, and their diversity patterns suggest mountains play a defining role.
- There is need for more research. In India in particular, several areas are under-studied.
- Some national programmes are trying to address these gaps, including the National Mission on Himalayan Studies, the National Mission for Sustaining the Himalayan Ecosystem, and the National Mission on Biodiversity and Human Wellbeing. They need to be strengthened, bolstered by the will to support basic research on diversity.
Improving battery technologies for speedy EV adoption
(GS Paper 3, Science and Technology)
Context:
- 2023 was a good year for Electric Vehicles (EV) in India with sales recording a 50% growth compared to 2022. While actual volumes remain small (6% of vehicles registered in 2023), the industry is poised for phenomenal growth with the Indian EV market expected to reach $100 billion by 2030.
- The projected growth of the EV market is dependent on advances in battery technology translating to better economics and enhanced user experience (longer range, faster charging and improved safety).
The lithium battery:
- Almost all EVs on the road today are powered by lithium-ion batteries. It consists of two electrodes (an anode and a cathode) separated by a liquid electrolyte. Lithium atoms in the anode give up electrons which travel to the cathode through an external wire, this stream of electrons provide the current which powers the motor of the vehicle.
- Simultaneously, lithium ions (now positively charged from loss of an electron) travel through the electrolyte to reach the cathode. During charging, the process is reversed with lithium ions being forced to travel back through the electrolyte to the anode.
- Lithium, the lightest solid element known to man, has a high propensity to give up its electron. Its small size enables the lithium ion to efficiently travel between electrodes through the electrolyte.
- This translates to lighter and smaller batteries with an ability to store large amounts of energy.
Gaps:
- However, today’s Li-ion batteries still leave a lot to be desired. Its energy density while high compared to earlier battery technologies, pales in comparison to petrol.
- There is a need to make batteries more affordable and increase their life-span.
- There are environmental concerns primarily related to the mining of lithium and other elements (such as cobalt, nickel).
Approaches to improve the battery:
- The efforts toward improving the EV battery can be broadly classified into three approaches.
Tweaking electrodes:
- The first approach retains the basic structure of the lithium-ion battery while making tweaks to the electrodes.
- An ideal electrode should be light weight; store a lot of lithium; provide sufficient pathways for lithium to easily enter and exit the electrode (=> higher voltages and faster charging); and be made of materials that are cheap, non-toxic and easily available. But invariably there are trade-offs involved.
- For example, Tesla uses cathodes based on Nickel-Manganese-Cobalt (NMC) and Lithium Iron Phosphate (LFP) in their batteries. While NMC batteries have high energy density and thus provide longer range, LFP batteries have longer life, better stability, are less toxic and have faster charging times.
Deploying sensing and control infrastructure:
- Another approach to improving battery performance involves deploying sensing and control infrastructure around the battery to increase safety, extend battery life and speed-up charging.
- For instance, a temperature sensor can be installed to detect dangerous conditions and shut down the battery, preventing a fire.
- Monitoring parameters such as internal temperature, voltage and current and appropriately modulating the charging current and voltage can result in faster charging while maintaining battery life.
- Advances in battery management and charging algorithms are generally easier to deploy since they do not involve any fundamental changes to the battery chemistry.
Solid-State Lithium Battery (SSB):
- There is considerable effort being invested in approaches that promise quantum jumps in battery performance.
- One such approach is the Solid-State Lithium Battery (SSB), which seeks to fix two common drawbacks in prevalent batteries. The liquid electrolyte used in EV batteries is highly flammable. The SSB replaces this with a heat resistant lightweight solid electrolyte.
- Further, the anode of an EV battery consists of a carbon based porous/layered scaffolding (typically graphite) which houses lithium atoms (a crude analogy is water stored in a sponge). The carbon scaffolding provides the required stability during charging and discharging, as lithium is reactive.
- However, the solid electrolyte in an SSB provides sufficient structural stability and good separation between the anode and the cathode, that the carbon scaffolding is no longer needed at the anode. This can significantly reduce the weight of battery and also improve charging speed.
Way Forward:
- India has a good eco-system that can support further progress in EV batteries, an expanding market, an environment that supports start-ups, friendly government policies, and successful home-grown EV companies (Ather, Ola Electric).
- Further, fundamental research in material science at India’s premier universities (IIT- Madras and Mumbai) and government research labs promotes innovation.
- The semiconductor industry in India (Texas instruments included) is also contributing advanced sensors and processors that will power the next generation of BMS.
