WHAT IS PALEOCLIMATOLOGY?

• Paleoclimatology is the study of the Earth's historical climatic conditions throughout different geological eras.

• Palaeoclimatologists work to comprehend our current and future climate trends by determining the causes of past climate shifts. 3, 4

• For studying the climate trends, spanning over thousands of years, scientists make use of “Paleo Proxies,” short for paleoclimate proxies or paleoenvironmental proxies, which are indicators used to reconstruct historical climate and environmental conditions.

• Tree rings, sediment cores, ice cores and organisms like diatoms, forams, and coral reefs are examples of useful proxies for the climate. 4

• On observing paleoclimate records, it is usually noted that a rise in carbon dioxide concentration in the atmosphere is associated with a rise in temperature. This means that climate change, on a broad scale, can be studied by referring to paleoclimate records. 1

• Reconstruction models of data on temperature profile of the planet over the last 2000 years show a significant rapid rise in temperature over the last 50 years. 1

HOW ARE PALEOPROXIES USED? (3, 4) 

1. Forams and Diatoms: The composition of these organisms' shells reflects the chemistry of the water at the time of shell development. It is possible to deduce the water temperatures in the past from the stable oxygen isotope ratios found in the shell. The heavier oxygen isotope is more abundant in shells formed in warmer waters because warmer water tends to evaporate off the lighter isotopes.

2. Tree rings: Temperature and precipitation variations can be deduced from the thickness of each ring since the ideal growing circumstances for that tree species will produce more growth and, consequently, thicker rings for a given year.

3. Sediment cores: Sediment-trapped charcoal can reveal information about previous wildfires. Given that each species has a narrow range of liveable conditions, remains of creatures like diatoms, forams and pollen within sediment can reveal shifts in the past climate.

4. Ice cores: To determine the ancient climate, deep ice cores can be examined for trapped gas, stable isotope ratios, and pollen.

HOW ACCURATE ARE THEY?

• A major assumption made about paleo proxies is that the environment and processes that led to their formation in the past is very similar to that of the present.

• Additionally, these proxies, which are basically fossils, being buried for years, can only record anomalies in the climate or shifts from the baseline temperature which is derived from thermometer recordings from the modern times. (6)

• The constant water currents surrounding the underwater paleo proxies and the microorganisms within them smoothens over the information carried by them over the years, making it practically impossible to estimate decadal or annual temperatures, let alone daily temperatures. (6)

• Also, paleo proxies are not reliable in giving accurate data as they are constantly subjected to changes due to the varying environmental conditions. (8)

WHAT ARE THE OTHER ALTERNATIVES?

• Studying the rate of radioactive decay of various isotopes over the years can help in estimating climate shifts in longer timescales, like the Holocene Epoch.

• The amount of the isotope that existed in the past can be determined if the rate of decay and present amounts of the isotope are known.

• Carbon and lead isotopes with half-lives ranging from 5000 to 10 million years can be used for the same purpose. (6)

• It has long been known that Radiocarbon (14C) offers a crucial dating technique over the last 55,000 years. Reconstructing comprehensive records of 14C has become more easier in recent years. Improved modelling of marine radiocarbon reservoir, new detail of pre-Holocene 14C levels using speleothems, lake macrofossils, and subfossil trees are few of the advances in this field. (7)

• However, as mentioned, these methods are only useful in studying the climate anomalies spanning over longer timescales and not for daily temperatures.

CLIMATE CHANGE AND THE AGE OF MAN (9, 10, 11)

Source: Drishti IAS / Anthropocene Epoch 

Source: Illinois State Museum / Paleoclimates and Ice Ages

• The age of man, referred to as the Holocene or Anthropocene era, commenced approximately 11,700 years ago following the end of The Ice Age. Throughout this era, numerous civilizations have risen and fallen, despite Homo sapiens having evolved and dispersed around the globe long before this period.

• A climatically related event was not usually the only or even the closest reason of the decline of different civilizations during this era, as per evidence.

• It should also be kept in mind that our bi-pedal ancestors have managed to withstand tremendous climate shifts over the course of hundreds of thousands of years.

• Paleoclimatology acts as retrospective tool that helps in predicting the evolution of the future climate, but only over longer timeframes.

• Even thermometer-based data are too few to be able to make credible claims regarding daily temperature records at the global scale.

• Therefore, while global warming can bring record-breaking warm months and years, we should exercise caution when it comes to news of apparently breaking records for warmth on a given day.

 CLIMATE TIPPING POINTS

• However, this does not mean that climate change must be taken on a lighter note.

• The concept of climate tipping points state that there are crucial benchmarks in a climate system that, if crossed, have the potential to cause a big shift in the state, with the change being irreversible.(12)

• In the early 2000s, scientists believed that most tipping points may be reached in the case of a 4°C rise in global temperatures. However, more recent analyses have indicated that going over 1.5°C of the global temperature can put multiple of these thresholds at risk of being crossed. (13)

• In comparison to the average temperature between 1850 and 1900, the Earth's surface temperature has already risen by around 1.2°C, and if the greenhouse gasses emissions do not decrease significantly, we are on course to cross the much feared 1.5°C threshold between 2026 and 2042. (13)

• Although we must acknowledge the fact that we have somewhat irrevocably altered the climate of the world, we cannot afford to continue with the same trend.

Source: Earth.org / Tipping points in climate change  

Way forward

Strategies To Mitigate the Climate Change at Global Level:(14)

• The United Nations Framework Convention on Climate Change (UNFCCC) (1994), aimed to stabilize greenhouse gas concentrations, outlining commitments for all parties, especially developed nations, to reduce emissions and aid developing countries; meanwhile, the Paris Agreement, established during from COP-21 in 2016, enhanced climate frameworks by introducing additional goals with a primary focus on limiting global temperature rise to 2 °C by 2100, with efforts to cap the increase at 1.5 °C.

• Decarbonization technologies- such as fuel switching to renewable energy or nuclear energy and carbon capture, storage and utilization in order to reduce CO2 emissions.

• CO2 negative emissions techniques- ocean alkalinity enhancement, soil carbon sequestration, afforestation and reforestation, wetland construction and restoration, as well as alternative negative emissions utilization methods such as mineral carbonation and using biomass in construction.

• Radiative forcing geoengineering technologies- the main objective being temperature stabilization or reduction of stratospheric aerosol levels.

COP 28:(15,16)

The 28th Conference of the Parties to the United Nations Framework Convention on Climate Change meeting convened at Dubai (UAE) from November 30th to December 12th, 2023. The key points were:

1. Global Goal on Adaptation (GGA): It aims to improve adaptation to climate change through initiatives which include reducing climate-induced water scarcity, promoting climate-resilient food and agriculture production, and enhancing resilience against health impacts related to climate by 2030.

2. Global Stocktake Text: It outlines eight steps to limit global temperature rise to 1.5 degrees Celsius, by urging the tripling of worldwide renewable energy capacity and doubling the annual rate of global energy efficiency improvements by 2030.

3. Global Renewables and Energy Efficiency Pledge: The Pledge involves signatories collaborating to triple global renewable energy capacity to at least 11,000 GW by 2030 and double the global energy efficiency improvement rate from around 2% to over 4% annually until 2030.

4. The Global Cooling Pledge for COP 28: 66 countries pledged together to reduce global cooling-related emissions in all sectors by at least 68% from 2022 levels, by 2050.

5. Loss and Damage Fund: The member nations have agreed to activate the Loss and Damage (L&D) fund, designed to provide compensation to countries facing climate change impacts, with a designated percentage allocated for Least Developed Countries and Small Island Developing States, to be overseen by the World Bank.

6. Climate Finance: The United Nations Conference on Trade and Development (UNCTAD) projects that, by 2025, affluent nations are obligated to provide developing countries with USD 500 billion as part of the New Collective Quantified Goal (NCQG) for climate finance.

7. Transitioning Away from Fossil Fuels to achieve net zero by 2050.

8. Declaration to Triple Nuclear Energy: The target is to triple the global nuclear energy capacity by 2050.

9. Coal Transition Accelerator: Introduced for knowledge-sharing and financial support in transitioning from coal.

10. Coalition for High Ambition Multilevel Partnership (CHAMP): 65 national governments signed commitments for enhanced cooperation with subnational governments in climate strategies.

11. Buildings Breakthrough Initiative: This initiative facilitated under UNEP and jointly led by France and the Kingdom of Morocco, hosted by the Global Alliance for Buildings and Construction (Global ABC), aims to establish near-zero emissions and resilient buildings as the standard by 2030.

Strategies To Mitigate the Climate Change at National Level:(17)

The Government of India launched National Action Plan on Climate Change (NAPCC) on 30thJune, 2008 which encompasses eight National Missions to tackle issues on climate change in the country. These include:

1. National Solar Mission

2. National Mission for Enhanced Energy Efficiency

3. National Mission on Sustainable Habitat

4. National Water Mission

5. National Mission for Sustaining the Himalayan Eco-system

6. National Mission for a Green India

7. National Mission for Sustainable Agriculture

8. National Mission on Strategic Knowledge for Climate Change

• The SAPCCs (State Action Plans on Climate Change) are implemented in 33 Indian states and UTs, outlining priority actions for climate change in sectors like water, agriculture, health, biodiversity, rural development, etc.18 Moreover, India’s commitment and accountability towards curbing climate change is commendable. Himachal Pradesh has been recognised as the first Carbon free state while the Palli Panchayat of Jammu has been declared as the country’s first ‘Carbon Neutral Panchayat.’

 CONCLUSION:

• Without thermometer records, it is impossible to predict the temperature of even a single day from the prior year.

• Far-fetched claims like the headlines stating that a specific day in July 2023 was the hottest in over million years can be a result of an increasing urge to report alarmist statements without considering the ramifications.

• Creating climate consciousness among the public by sacrificing scientific accuracy can cause more harm than good in the long run.

• Even if the overall goal is positive, incorrect and poorly investigated methods to reach that goal cannot be justified as this might damage the credibility of climate community.

• Responsible journalism, avoiding sensationalized headlines, especially for sensitive topics such as climate change, should be given careful consideration.

• The confidence and trust that today's societies have placed in scientists should not be breached as this could result in permanent setback to the endeavours to enhance worldwide involvement in climate-responsible negotiations, the drive of governments to fulfil their climate commitments, and the grassroots campaigns that compel governments and corporations to take responsible actions.

References:

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4.     Microbiological Life Educational Sources (2023) Paleoclimatology, Paleoclimatology: How Can We Infer Past Climates? Available at: https://serc.carleton.edu/microbelife/topics/proxies/paleoclimate.html

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5.     National Centers for Environmental Information (NCEI) (2023) Climate change in the context of Paleoclimate, Climate Change in the Context of Paleoclimate. Available at: https://www.ncei.noaa.gov/news/climate-change-context-paleoclimate

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7.     Heaton, T.J., Bard, E., Bronk Ramsey, C., Butzin, M., Köhler, P., Muscheler, R., Reimer, P.J., Wacker, L., 2021. Radiocarbon: A key tracer for studying Earth’s dynamo, climate system, carbon cycle, and Sun. Science 374, eabd7096. https://doi.org/10.1126/science.abd7096

8.     Borzenkova, I., Zorita, E., Borisova, O., Kalniņa, L., Kisielienė, D., Koff, T., Kuznetsov, D., Lemdahl, G., Sapelko, T., Stančikaitė, M., Subetto, D., 2015. Climate Change During the Holocene (Past 12,000 Years), in: The BACC II Author Team (Ed.), Second Assessment of Climate Change for the Baltic Sea Basin, Regional Climate Studies. Springer International Publishing, Cham, pp. 25–49. https://doi.org/10.1007/978-3-319-16006-1_2

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(Accessed: 26 February 2024).

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