ESS-102: Climate Action & IPCC

• ESS-102 concerns Environmental Science and Sustainability

The 2030 Agenda for Sustainable Development

• The agenda outlines Sustainable Development Goals

Goal 13: Climate Action

• Goal 13 is to take action to combat climate change and its impacts

Intergovernmental Panel on Climate Change (IPCC)

• The IPCC is the United Nations body for assessing the science related to climate change
• The IPCC provides policymakers with regular scientific assessments on climate change, its implications, potential future risks, adaptation, and mitigation options
• The IPCC prepares comprehensive assessment reports about scientific/technical/socio-economic knowledge on climate change, its impacts/future risks, and options for reducing its rate
• The Sixth Assessment Report was released in 2023

Global Surface Temperature

• Global surface temperature has increased by 1.1°C from 2011-2020 compared to 1850-1900
• Observed warming comes from emissions from human activities with GHG warming partly masked by aerosol cooling from 2010–2019

Earth's Atmosphere: Chemical Composition and Vertical Structure

• The atmosphere is composed as follows:
• Nitrogen (N2) makes up 0.78 of the atmosphere
• Oxygen (O2) makes up 0.21
• Carbon dioxide (CO2) is measured at 386 ppmv
• Water vapor (H2O) is ≤0.03
• Ozone (O3) is ≤ 10 ppmv
• Argon (Ar) is 0.0093

Troposphere

• The Troposphere extends 12 kilometers from Earth's surface
• About 99% of all water vapor and aerosols reside here
• Temperature decreases with increasing altitude because of radiative cooling
• This is the densest atmospheric layer and the location of Earth's weather, cloud generation, and most aviation activity

Stratosphere

• The Stratosphere is located 12 to 50 kilometers above Earth
• It contains the ozone layer, which protects from solar UV radiation
• Temperature increases with altitude due to UV absorption by ozone
• Nearly cloud- and weather-free, polar stratospheric clouds are sometimes present at low, cold altitudes, and it's the highest part of atmosphere jets can fly

Mesosphere

• The Mesosphere is located 50 to 80 kilometers above Earth's surface
• Temperature decreases as altitude increases because of radiative cooling
• The top of this layer is the coldest place within the Earth system at -85 degrees Celsius
• Most meteors burn up here, with sounding rockets and rocket-powered aircraft able to reach it

Thermosphere

• The Thermosphere is located 80 to 700 kilometers above Earth
• Very short wavelength UV is absorbed by oxygen, thus heating the region
• The atmosphere becomes ionized or the ionosphere, causing reflection of radio waves
• The aurorae are sometimes seen and the International Space Station orbits here

Weather and Climate

• Weather refers to short-term atmospheric conditions, like precipitation, temperature, humidity or atmospheric pressure
• Climate is atmospheric changes over longer periods of time, usually 30 years or more
• Climate and weather are interlinked
• Climate is the average of weather conditions over time
• A change in climate can lead to changes in weather patterns

Climate Change

• Indicators
• The warming of average global surface air temperature since 1850-1900 has occurred
• The troposphere has warmed since 1979
• The lower stratosphere has cooled since the mid 20th century
• Large scale precipitation changes as well as upper troposphere humidity changes since 1979
• The Hadley Circulation has expanded since the 1980s
• The ocean's heat has increased since the 1970s
• There have been salinity changes since the mid-20th century
• The global mean sea level has been rising since 1970
• The arctic sea ice has been decreasing since 1979
• There has been a reduction in Northern Hemisphere snow cover since 1950
• Greenland ice sheet mass loss has occurred since the 1990s
• Antarctic ice mass sheet loss has occurred since the 1990s
• Glaciers are in retreat
• There has been an increased amplitude of the seasonal cycle of atmospheric CO2 since the early 1960s
• The global surface ocean has seen acidification
• The mean surface air temperature over land is about 40% larger than the global mean warming
• The global climate system has been warming since preindustrial times

Impacts of Climate Change

• Climate change has adversely affected human physical and mental health in assessed regions, contributing to humanitarian crises when climate hazards interact with high vulnerability
• Climate change has an adverse impact on most sectors

Factors Contributing to Climate Change

• Human-caused climate change results from more than a century of net GHG emissions from energy use, land-use, lifestyle, consumption, and production patterns

Greenhouse Effect

• The greenhouse effect is when gases in Earth's atmosphere trap the Sun's heat
• This process makes Earth warmer and habitable

Greenhouse Gases

• CO2 is released through natural processes; atmospheric CO2 concentration has increased because of the burning of fossil fuels and large-scale deforestation
• Methane is produced naturally through decomposition; human activity has displaced the natural balance, with large amounts released by cattle farming, landfill waste dumps, rice farming, and traditional oil and gas production
• Nitrous oxide is produced through the large-scale use of commercial and organic fertilizers, fossil-fuel combustion, nitric-acid production, and biomass burning

Climate Change Solutions

• Reduce fossil fuels, move to renewable energy, upgrade infrastructure, and relocate closer to work.
• Reduce waste and convert waste into energy
• Stop cutting down trees
• Future Fuels (Biofuels)
• Have an environmentally friendly attitude
• Stop wasting electrical energy

Space Debris

• Many satellites fail before completing their design life, or have exploded.
• The last stages of satellite-launching rockets and other spare parts float in space
• Some of these objects have burnt to ash as they fell towards Earth
• Objects in space that have no use are known as space waste, with is widely known as space debris
• Any man-made object in space that have no use is a space junk, waste or debris

Space Debris: Composition

• Debris includes satellites that have completed their lives or stopped functioning properly, along with exploded satellites and pieces of rockets
• More debris: used rocket engines, frozen fuel dust, experimental animal corpses, waste discarded by astronauts as well as tools and equipment

Space Debris Amounts

• In 2019, the US Space Surveillance Network identified about 20,000 large, trackable objects in space
• 2,200 operational satellites exist
• 34,000 objects are larger than 10 cm, 9 lakh objects range from 1 to 10 cm, and 128 million objects are less than 1 cm in size
• There is no record of the pieces smaller than above, which are often called micro debris

Growth of Space Debris Over Time

• Russian Cosmos-1275 was the first satellite thought to be damaged by space debris and destroyed on 24 July 1981
• In July 1996, France's Cerise satellite was damaged by an Ariane 1-H10 rocket stage
• On 29 March 2006, the Russian Express A.M. Communication satellite 11 was damaged
• In the US, NASA's space shuttle Challenger's second vehicle, STS-7, was hit by space debris, shattering its window

Space Debris Cleaning Methods

• Self-cleaning involves satellites carrying extra fuel than what is required to de-orbit, pushing the satellite out of its designated spot at the end of its life
• External cleaning involves special equipment and robots which would push large space debris into a graveyard orbit
• While still under development, one method would capture debris with a net or robotic arm, tow it into an unusable “graveyard orbit,” then release it