This document provides an overview of key concepts and terminology related to climate change, including: - The difference between weather (atmospheric conditions at a given time) and climate (average weather over a longer period). - How climate change refers to changes in climate characteristics like temperature, rainfall, and weather events over long periods. - Evidence that the global average temperature is rising due to increased greenhouse gas emissions since the industrial revolution, and 19 of the last 20 years have been the warmest on record. - The main impacts of climate change include rising sea levels, stronger hurricanes, droughts and heat waves, and effects on agriculture, water resources, and human health.

1. Rezwan Siddiqui
Senior Lecturer
East West University
Basics of Climate Change: Concepts
and Terminologies
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2. Weather What is happening in the atmosphere
at any given time
Climate Average weather over longer time frame
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Climate Change Science

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Weather
Yesterday’s wind direction, speed and
temperature
Source: www.cpc.ncep.noaa.gov
Source: https://earth.nullschool.net/
Climate
3 – month’s Average Temperature

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Climate and Climate Change

5. What is climate change?
The planet's climate has constantly been changing over geological time.
The global average temperature today is about 15 degree Celsius, though
geological evidence suggests it has been much higher and lower in the
past.
Climate Change refers to changes in climate characteristics including
temperature, humidity, rainfall, wind, and severe weather events over long
periods.
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https://climate.nasa.gov/
Global Land-ocean Temperature Index
Nineteen of the warmest years have occurred since 2000, except for 1998. The year 2020
tied with 2016 for the warmest year on record since record-keeping began in 1880

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Global Warming from 1880 to 2020
https://climate.nasa.gov/

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Causes of Climate Change: GHG Effect

9. Causes of Climate Change: GHG Effect
Since the beginning of 20th century, scientists have been observing a change in the
climate that can not be attributed to any of the “natural” influences of the past only.
This change in the climate, also known as GLOBAL WARMING, has occurred faster than
any other climate change recorded by humans. The main cause of global warming is
the increased concentration of GHGs in the atmosphere since the industrial revolution
in the late 18th century.
The increased amount of GHGs which absorbs and re-emit thermal radiation, has
directly led to more heat being retained in the atmosphere and thus an increase in
global average surface temperatures. The increase in temperature is also leading to
other effects on the climate system. Together these affects are known as anthropogenic
(human caused) CLIMATE CHANGE
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The Gases that Contribute to the Greenhouse Effect

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https://climate.nasa.gov/
Global CO2 Level

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Source: https://www.nature.com/articles/d41586-020-02116-
Global Methane Levels Soar to Record High

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Impacts of Climate Change

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Arctic likely to become ice-free

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Sea level rise is caused primarily by two factors related to global warming:
the added water from melting ice sheets and glaciers and the expansion of
seawater as it warms.

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Impacts of Climate Change and GHG Emission
• Change will continue through this century and beyond
• Temperatures will continue to rise
• Changes in precipitation patterns
• More droughts and heat waves
• Hurricanes will become stronger and more intense

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Cumulative Risks
from Climate
Change

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Climate Change
and Health

21. Impact of climate change in Bangladesh
• CC will result in increasing and severe frequent tropical cyclones, with higher wind speeds and
storm surges causing more damages in the coastal region
• Heavier and irregular rainfall during the Monsson will result in:
• Higher river flows, causing over-topping and breaching of embankments, and
widespread flood
• River bank erosion resulting in loss of homes and agricultural land
• Increased sedimentation in the riverbeds leading to drainage congestion
• Melting of the Himalayan glaciers will lead to higher river flows
• Sea level rise, leading to the submerge of the low lying coastal region and Saline water intrusion
• Warmer and more humid weather, leading to the increasing prevalence of disease. Climate
change is likely to increase the incidence of water-borne and air-borne disease, bacteria, and
parasites.
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22. Impact of climate change in Bangladesh
• Each of these changes is likely to seriously affect agriculture (crops, livestock, and fisheries).
The higher temperature and changing rainfall patterns, coupled with increased flooding,
rising salinity in the coastal belt and droughts are likely to reduce crop yields and crop
production
• Shortage of safe drinking water is likely to become more pronounce, especially in the
coastal belt and in drought-prone areas in the north-west
• Increase riverbank erosion and saline water intrusion in coastal areas are likely to displace
hundreds of thousands of people
• All of these changes threaten the food security, livelihoods and health of the poor
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“The climate system is complex, as are its interactions with humanity, and beyond
these ‘big picture’ forecasts lie many more specific questions. How much will sea
level rise, and how quickly? How will forests respond to increased CO2 and
changing precipitation patterns? Will life be able to adapt to the changing
conditions? Research into the nuances of these and similar questions sometimes
yields unclear or conflicting results. The answers may vary geographically and be
confounded by natural variability, so that attribution of certain events to climate
change is difficult. Future answers to these questions are typically calculated from
models based on mathematical representation of processes or statistical
regression of past data, both of which have limitations. Predictions are also
uncertain because human and societal actions are unknown.
All of this makes precise predictions of impacts and timelines challenging. Yet,
exactly these are highly relevant for informing mitigation policies and deciding how
to react to the varied consequences of climate change.”
https://www.nature.com/articles/s41558-019-0627-1

24. Climate Change Adaption,
Mitigation and Development
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25. What to do?
Mitigation A human intervention to reduce the sources or
enhance the sinks of greenhouse gases (GHGs).
Adaptation The process of adjustment to actual or expected climate
and its effects.
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26. What to do?
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27. What to do?
Prevent Mitigate Adapt
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28. - Contributes to the reduction of GHG intensity per unit of output
- Limits the burning of fossil fuels for energy and uses lower carbon or
renewable sources
- Uses energy more efficiently in agriculture, homes, offices and industries
- Plans transport systems and urban development appropriately
- Reduces emissions from poor forest and land use practices
- Stores carbon in the soil through conserving forests and managing land
more sustainably.
An activity is considered Mitigation if it:
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29. - Reduces the risk, exposure or sensitivity of human or natural
systems to climate change and climate variability
- Increases the potential or capability of a system to adapt to effects
and impact of climate stimuli
- Builds problem solving capacity to develop responses to climate
variability and change
- Incorporates climate risk information into decision-making.
An activity is considered Adaptation if it:
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30. What to do?
Prevent Mitigate Adapt
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There is growing recognition that mitigation and adaptation efforts are
insufficient to prevent or alleviate all climate change impacts. The term loss
and damage usually refers to these ‘residual’ impacts.
Loss and damage can be the result of severe weather events or slow onset
events such as sea level rise or desertification. Because the impact of these
events is not always quantifiable, a distinction has been made between
economic and non-economic loss and damage
Climate Change Loss and Damage

33. "…contributes to the integration of climate change concerns with the recipient
countries' development objectives through institution building, capacity
development, strengthening the regulatory and policy framework, or research…".
It identifies three options: that adaptation/mitigation is a "principal objective",
"significant objective", or "not targeted to the policy objective". For an activity to
be classified as having adaptation/mitigation as a "principal objective", it must be
established that it "would not have been funded but for that
[adaptation/mitigation] objective". This is in contrast to activities categorized as
having adaptation/mitigation as a "significant objective" which have "other prime
objectives, but have been formulated or adjusted to help meet climate concerns."
Handbook on OECD-DAC Rio Markers on climate change
defines that an activity "should be classified as climate-change-
related" if it
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Adaptation and Development

34. • Trying to draw sharp distinctions between “adaptation” and “development” is not necessarily helpful or
reflective of what was a reality on the ground. Adaptation to climate change project proposals looks very
similar to development projects.
• Understanding the climate risk context is the crux of adaptation.
• “Adaptation or development” is not an either-or choice.
• Adaptation often requires simultaneous work at multiple points on the continuum.
• Full integration of adaptation into development is among the most transformational processes in the
climate change space. Long-term success means abandoning the “adaptation versus development”
function of the continuum.
• The economic, social and environmental costs of development will increase due to climate change
Adaptation and Development
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35. https://www.weforum.org/agenda/2019/03/climate-change-is-a-security-threat-let-us-act-now/
Climate change is a security threat. We must act now
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36. • https://www.ipcc.ch/assessment-report/ar6/
• https://climatescience.org/
• https://climate.nasa.gov/
• https://earthobservatory.nasa.gov/global-maps
• https://www.climate.gov/teaching
• https://www.globalchange.gov/
• https://climateanalytics.org/
• https://www.newscientist.com/article/dn11462-climate-change-a-guide-for-the-perplexed/
• https://climateanalytics.org/media/decarbonisingasia2019-profile-bangladesh-climateanalytics.pdf
Useful Reference to Learn more about Climate Change
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37. Rezwan Siddiqui
Senior Lecturer
East West University
rezsid@gmail.com
Thank you
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