Chapter 1 - Foundations of Climate Change: What Is Climate Change?

Chapter 1 - Foundations of Climate Change: What Is Climate Change? Difference between WEATHER and CLIMATE Weather is the weather on a day-to-day basis. Meanwhile, climate is the weather over a long period of time. - in which data is collected Climate Change The long-term differences in the statistics of weather measured over multi-decadal periods. Global Warming vs Climate Change They are interchangeable but Climate Change refers to all aspects of the climate ( precipitation/ sea level rise) Warming Oceans oceans absorbing increased atmospheric heat Sea Level Rise 1. Melting ground Ice 2,Water expands when it is warm What does historical data about the climate tell us? 1. An ice age temperature range is 6C so the 1C increase is significant. 2. Mega cities have only been around since the 1800 and the range temperature change for that time has been noted. 3. The warming we are experiencing is more rapid. 100years = 1C is 16x faster than the average rate from last ice age. GHG Greenhouse gases in our atmosphere increase + atmosphere traps heat = higher temperatures General trends for modern day climate change 1. Warming of the planet is not uniform - Land warms faster than oceans and the North heated faster than the South 2. Sea level rise - melting sea ice and thermal expansion Climate Change before humans 1. The planet has been cycling between cold periods, known as ice ages 2. the global average tempera-ture difference between an ice age and an interglacial is about 6°C - so 1 degree is significan because of how rapid it is. 3. 16 x faster than the average rate of cooling How can Climate Change be measured? 1. Tree rings 2. Corals 3. Ice cores 4. Ocean Sediment cores Causes of climate Change 1. Energy Balance 2. Green House Effect Energy Balance Most important rule of the Earth's climate - energy balance 30% of incoming sunlight is reflected back to space -(means) infrared radiation = heat. The amount of heat radiated is determined on planet temperature GHG GHG are a part of the atmosphere and absorb infrared radiation = earth heats up with more in the atmosphere GHG = Water Vapor (traps the most heat) th eCO2 Carbon dioxide Increase CO2 in atmosphere increase in planetary temperatures increase due to combustion of fossil fuels - industrial revolution. Human are main cause of increase Half of CO2 released is absorbed in the oceans. Methane Powerful greenhouse gas on a Human's Impact on the Climate 1. Significant anthropogenic changes to the planet. 2. Difference between incoming energy (sunlight) absorbed by the Earth and the outgoing energy (infrared radiation) emitted by the Earth back to space. Attributions to modern warming Tectonic Processes - the movement of a continent toward the poles can lead to the growth of an ice sheet on the continent. Because ice sheets are reflective, the growth of a continental ice sheet will lead to more incident sunlight being reflected back to space, which will tend to cool the climate. Output of the Sun - eliminate as modern reason, not enough data Orbital Variations - the closer the earth is to the sun the more heat Unforced Variability - El Nino NOT LIKELY REASON GHG - adding carbon dioxide, or any other gas that absorbs infrared radiation, to the atmosphere should warm the planet by affecting the planet's energy balance. Second, it is a fact that humans are adding carbon dioxide to the atmosphere. The timing of warming, beginning in the nineteenth century after the industrial revolution, and the magnitude of the warming also match scientific theory. Finally, the geologic record shows that changes in climate are frequently associated with changes in greenhouse that adding carbon dioxide, or any other gas that absorbs infrared radiation, to the atmosphere should warm the planet by affecting the planet's energy balance. Second, it is a fact that humans are adding carbon dioxide to the atmosphere. The timing of warming, beginning in the nineteenth century after the industrial revolution, and the magnitude of the warming also match scientific theory. Finally, the geologic record shows that changes in climate are frequently associated with changes in greenhouse gases. Shared Socioeconomic Pathways (SSPs) SSP1 - is a sustainable world where the world's econo-mies gradually shift toward a more environmentally friendly path. B SSP2 - is a world that follows the trends of our world today, leading to generally declining emissions over the twenty-first century due to widespread adoption of renewable energy (although slower than in SSP1). SSP3 - a world that follows the trends of our world today, leading to generally declining emissions over the twenty-first century due to widespread adoption of renewable energy (although slower than in SSP1). SSP5 - a world simil