Climate, Weather and the Greenhouse Effect

Instructor Background

  • Dr. Jatin Kala (J.Kala@murdoch.edu.au) is a Senior Lecturer in Atmospheric Science at Murdoch University.

  • Education: - BSc (Hons) and PhD in Environmental Science from Murdoch University (2003-2011).

  • Professional Experience:- Research Fellow in Climate Science at UNSW (2012-2015) for 3.53.5 years.

    • Lecturer in Atmospheric Science at Murdoch University since June 20152015.

    • Senior Lecturer in Atmospheric Science at Murdoch University since November 20182018.

  • Research & Teaching:- Supervises Honours, Masters, and PhD students in areas like regional climate modelling, land-atmosphere interactions, extreme weather, and air quality.

    • Teaches and coordinates ENV242 - Atmospheric and Climate Science.

    • Teaches half the lectures in PEN597 - Climate Change Science and Policy.

    • Lead author for Chapter 11 of the IPCC special report on global warming of 1.51.5°C.

Climate versus Weather
Definitions

  • Weather: The atmospheric conditions at a specific place and time, encompassing short-term fluctuations in temperature, precipitation, humidity, wind, and atmospheric pressure. It describes the current state of the atmosphere and can change rapidly, often from minute-to-minute, hour-to-hour, or day-to-day. Weather is what you experience when you step outside.

  • Climate: The long-term average of weather patterns in a region, typically averaged over a period of 30 years or more. It describes the expected weather conditions for a given place and time of year based on historical data. Climate includes statistical descriptions like average temperatures, average rainfall, and the frequency of extreme events, defining a region's typical atmospheric behavior over an extended period. For instance, knowing that winters are generally cold and snowy in a particular region describes its climate.

Common Misconceptions

  • Confusing a single weather event with climate trends: A common mistake is to interpret an individual cold snap or a particularly hot summer as evidence for or against long-term climate change. Climate refers to the statistical distribution and patterns of weather over many decades, not a single day's or season's conditions. For example, a severe blizzard in winter does not negate global warming, as it is a short-term weather phenomenon.

  • "Climate change isn't real because it's cold today": This statement arises from a fundamental misunderstanding that climate should reflect the current local temperature rather than global, long-term averages. Global climate change refers to a shift in these long-term average conditions over the entire planet, leading to changes in temperature, sea levels, and precipitation patterns across many regions, even if some areas experience colder weather at times.

  • Attributing all extreme weather to climate change: While climate change is projected to increase the frequency and intensity of certain extreme weather events (such as heatwaves, heavy rainfall, or droughts) due to altered atmospheric conditions and energy balances, it is inaccurate to directly and solely attribute every single extreme event to climate change without specific scientific analysis. Each event has its own complex meteorological drivers, though its characteristics (e.g., intensity) might be influenced by a changing climate.

  • Believing climate is static: Climate is not fixed; Earth's climate has naturally varied throughout history due to factors like orbital changes and volcanic activity. However, current climate change is distinct due to its rapid pace and the prominent role of human activities in driving it, primarily through greenhouse gas emissions.