• To meet the 1.5°C targets, widespread 'system transformations' across the energy, buildings, land, transport and other sectors are required, which will entail adopting low-emission or zero-carbon development pathways in each sector. And solutions are available at reasonable prices.
• Since 2010, the costs of low-emission technology have steadily fallen continuously. On a unit cost basis, solar energy has dropped by 85%, wind energy by 55%, and lithium-ion batteries by 85%.
• Their deployment, or use, has increased many times since 2010 — ten times for solar and one hundred times for electric vehicles.
• Among the numerous solutions are the reduction of fossil fuel use in the energy sector, demand management and energy efficiency in the industrial sector, and the adoption of 'sufficiency' and efficiency principles in building construction.
• It also states that demand-side mitigation, such as adopting plant-based diets or shifting to walking and cycling, "can reduce global GHG emissions in end-use sectors by 40-70 percent by 2050 compared to baseline scenarios" and boost wellbeing.
• The majority of the potential for demand-side mitigation is now concentrated in developed countries.
• According to the IPCC, low-cost climate mitigation solutions could cut world GHG emissions in half by 2030. Indeed, the long-term benefits of limiting global warming outweigh the costs.
• Investing in decarbonization would have a minimal impact on global GDP.

• The  Assessment Reports, the first of which was published in 1990, are the most comprehensive assessments of the state of the Earth's climate.
• The IPCC publishes assessment reports every few years (about seven years).
• Hundreds of experts go through every piece of relevant, published scientific information in order to develop a common understanding of the changing climate.
• The 4 subsequent evaluation reports, each thousand pages long, were published in 1995, 2001, 2007, and 2015.
• These have served as the foundation for the global response to climate change.
• Each assessment report has expanded on the work of the previous ones over the years, providing more evidence, information, and data.
• As a result, most conclusions about climate change and its consequences now have far greater clarity, certainty, and a wealth of new evidence than earlier.
• These negotiations resulted in the Paris Agreement and, before, the Kyoto Protocol.
• The Paris Agreement was negotiated in response to the Fifth Assessment Report.
• Three working groups of scientists produced the Assessment Reports.
  • Working Group I focuses on the scientific basis for climate change.
  • Working Group-II investigates potential impacts, vulnerabilities, and adaptation issues.
  • Working Group-III - Addresses climate change-related activities that can be taken.

First Assessment Report (1990)

• Emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases.
• Global temperatures have risen by 0.3 to 0.6 degree Celsius in last 100 years. In business-as-usual scenario, temperatures likely to increase by 2 degree Celsius compared to pre-industrial levels by 2025, and 4 degree Celsius by 2100
• Sea-level likely to rise by 65 cm by 2100
• This report formed the basis for negotiation of the UN Framework Convention on Climate Change in 1992.

• The second Assessment Report (1995) revised the projected rise in global temperatures to 3 degrees Celsius above pre-industrial levels by 2100, and sea-level rise to 50 cm, in light of more evidence. Global rise in temperature by 0.3 to 0.6 degree Celsius since the late 19th century was “unlikely to be entirely natural in origin”, it said.
• AR2 was the scientific underpinning for the Kyoto Protocol of 1997

• The third Assessment Report (2001) revised the projected rise in global temperatures to 1.4 to 5.8 degrees Celsius by 2100 compared to 1990. The projected rate of warming was unprecedented in the last 10,000 years, it said. The report predicted increased rainfall on average, and that by 2100, sea levels were likely to rise by as much as 80 cm from 1990 levels.

• The fourth Assessment Report (2007) said greenhouse gas emissions increased by 70 per cent between 1970 and 2004, and atmospheric concentrations of CO2 in 2005 (379 ppm) were the most in 650,000 years. In the worst-case scenario, global temperatures could rise 4.5 degrees Celsius by 2100 from pre-industrial levels, and sea levels could be 60 cm higher than 1990 levels.
• The report won the 2007 Nobel Peace Prize for IPCC. It was the scientific input for the 2009 Copenhagen climate meeting.

• The fifth Assessment Report (2014) said more than half the temperature rise since 1950 was attributable to human activities, and that the atmospheric concentrations of carbon dioxide, methane, and nitrous oxide were “unprecedented” in the last 800,000 years.
• AR5 formed the scientific basis for negotiations of the Paris Agreement in 2015.

• The World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established IPCC in 1988 to provide policymakers with regular assessments of the scientific basis of climate change, its impacts, and future risks, as well as options for adaptation and mitigation.
• IPCC assessments serve as a scientific basis for governments at all levels to establish climate-related policies, and they serve as the foundation for negotiations at the UN Climate Conference — the United Nations Framework Convention on Climate Change (UNFCCC).
• IPCC is an international body in charge of assessing climate change science.

Least Developed Countries Emissions

• Carbon inequality persists, with Least Developed Countries (LDCs) accounting for only 3.3 percent of global emissions in 2019.
• In the period 1990-2019, their average per capita emissions were only 1.7 tonnes of CO2e, compared to the global average of 6.9 tCO2e.
• In the period 1850-2019, LDCs contributed less than 0.4 percent of the total historical CO2 emissions from fossil fuels and industry.
• In 2019, 41 percent of the world's population lived in countries with per capita CO2 emissions of less than 3 tCO2e.

• The report identifies India as one of the vulnerable hotspots, with several regions and important cities facing very high risk of climate disasters such as flooding, sea-level rise and heat-waves. Mumbai is at high risk of sea-level rise and flooding.
• Ahmedabad faces serious danger of heat-waves.
• Several cities, including Chennai, Bhubaneshwar, Patna and Lucknow, are approaching dangerous levels of heat and humidity.
• Infrastructure, including transportation, water, and sanitation and energy systems has been compromised by extreme and slow-onset events, with resulting economic losses, disruptions of services and impacts to well- being.
• Urban India is at greater risk than other areas with a projected population of 877 million by 2050, nearly double of 480 million in 2020.

• IPCC reports form the scientific basis on which countries across the world build their policy responses to climate change.
• These reports, on their own, are not policy prescriptive: They do not tell countries or governments what to do. They are only meant to present factual situations with as much scientific evidence as is possible.
• And yet, these can be of immense help in formulating the action plans to deal with climate change.
• These reports also form the basis for international climate change negotiations that decide on the responses at the global level. It is these negotiations that have produced the Paris Agreement, and previously the Kyoto Protocol.

• In developing countries and for poor and vulnerable people, implementing the response would require financial, technological and other forms of support to build capacity, for which additional local, national and international resources would need to be mobilized.
• The advancement in the solar energy, wind energy, hydropower, bio-based feedstock’s and substitution are some of the new more suitable option for power and a great extent of greenhouse emission can be reduced by switching to these energies. Hydrogen, bio-based feedstock and substitution
•  Global and regional land-use and ecosystems transitions and associated changes in behaviour that would be required to limit warming to 1.5°C can enhance future adaptation and land-based agricultural and forestry mitigation potential.
• Improving the efficiency of food production and closing yield gaps have the potential to reduce emissions from agriculture, reduce pressure on land and enhance food security and future mitigation potential
• A mix of mitigation and adaptation options implemented in a participatory and integrated manner can enable rapid, systemic transitions in urban and rural areas that are necessary elements of an accelerated transition to 1.5°C.
• The pathways of 1.5°C typically rely on Bioenergy with Carbon Capture and Storage (BECCS), Afforestation and Reforestation (AR), or both, to neutralize emissions that are expensive to avoid or to draw down CO2 emissions in excess of the carbon budget.