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