The different evidences about climate change and their reliability
Ice cores - (The ice has small air bubbles of ancient air that has different gases and isotopes inside it that show what the temperature was at the time of the formation of the ice.). Most reliable, give information.
Dendrochronology - the tree rings show the temperature (wide ring=warmer οr wetter , narrow rings=colder or drier). Reliable only for certain regions and don’t go back far enough.
Landscapes + geology/fossils - oldest but less accurate as the data can be altered easily and its hard to link it to a time period.
Paintings + diaries - unreliable as they could’ve made it up, not empirical. Least reliable as its subjective, not scientific, only cover a short time period and aren’t based on scientific data.
Theories about the causes of natural climate change
Sun spots - they are cooler, darker spots on the earth where slightly more solar energy is given off
Volcanic eruptions - Asteroids / Volcanoes - linked to global cooling (SO2 and dust blocking solar energy from entering)
Milankovitch cycles - Changes in the earth’s orbit around the sun - changes the distribution of the insolation and seasons. It becomes more elliptical or circular.
Natural green house effect vs enhanced green house effect
Normal - ray of light passes through the atmosphere. Radiation is absorbed by the earths surface. Rays are then reemitted. Enhanced - increase in gases means that more solar energy gets trapped, leading to the atmosphere being warmed up by roughly 1.5 degrees.
Greenhouse gases prevent the earth from being a ball of ice. They add around 18 degrees to the earth’s temperature by absorbing energy from the UV.
The enhanced greenhouse effect is the additional greenhouse gases that humans have accumulated in the atmosphere, causing more energy to be absorbed and that causes the planet to heat up more.
Overall greenhouse gas emissions
75% - CO2
17% - CH4
6% - N2O
2% - Other
Transport Contribution to Greenhouse Gases %, Use + Main emissions
15.9%, Road (and rail, air & ship) -> CO2
Electricity and Heat and other fuel Contribution to Greenhouse Gases %, Use + Main emissions
33.4%, Buildings (and fuel combustion) -> Mainly CO2 but also CH4
Buildings, Manufacturing and Construction Contribution to Greenhouse Gases %, Use + Main emissions
17.9%, Buildings + Other industry -> CO2
Industrial Processes (inc. fugitive emissions) Contribution to Greenhouse Gases %, Use + Main emissions
11.4%, Cement + Chemical & Petrochemical -> CO2
Agriculture Contribution to Greenhouse Gases %, Use + Main emissions
11.8%, Livestock + Soil -> N2O and CH4
Waste Contribution to Greenhouse Gases %, Use + Main emissions
3.2, Landfill, wastewater -> CH4 and some N2O
Land use and deforestation
Contribution to Greenhouse Gases %, Use + Main emissions
6.5%, Burning, crop land and forest land -> CO2
Factors affecting the risk of a country/area to climate change.
Hazards (H), Vulnerability (V), Capacity to cope (C).
H - flooding + storms and sea level rise, heatwaves, changing seasonal norms, droughts
V - altitude, location, age (population structure) - places with an aging population are more vulnerable, economic structure (kind of jobs e.g. farming)
C - economy (can they afford AC and flood defences, do they have good healthcare), alert systems / government planning -> legislation, education (do people know how to cope)
In an equation: R = (V x H) / C
UK Weather + climate
UK has a cool and mild climate with changeable weather.
Factors that influence the weather in the UK
LAMAS
Latitude
Air masses (4 of them: Polar Maritime/Continental, Tropical Maritime/Continental - Warmer tropical air meets colder arctic air in the air mass above us. This is what causes the large changes in the weather we experience and fuels our more severe storms.) - atmospheric pressure (as we sit in between the Polar and Ferrel cells, we have a temperate climate. (Wind blows down the concentration gradient)),
Marine influence
Altitude
Seasons
Climate change impacts on UK
warmer + wetter winter
hotter and drier summers
storms get more frequent and more intense.
Milder temperature
2070 vs 1990
All assuming the world continues to produce emissions like now
* Winter are 1-4.5 C warmer
* Winters are up to 30% wetter
* Summers are 1-6 C warmer
* Summer are up to 60% drier
* Hot summer days are 4-7 C warmer
* Exceeding 30C for 2 days is 16x more likely in the south
* Exceeding 40C has the same chance of exceeding 30C in 1990
* Days when rainfall excess 30mm per hour happens twice as often
* Intensity of rain increases from 20%-25%
* In the south, the average hottest day in the summer will be roughly 40C
Consequences of more frequent and intense rainfall in UK
- Intensity of rain will increase (how heavy rain occurs).
- In summers, a 20% increases and in winter, a 25% increase of rainfall.
- Hourly rainfall exceeding 30mm per hour will be a threshold for flash flood alerts and we will meet it twice as often than we did in 1990.
- A greater risk of flooding will also happen and that will heavily impact the environment and our daily lives.
UK government reaction to climate change
The government has assigned 5.2 billion for new flood and coastal defences by 2027 as part of the green industrial revolution
Climate change’s impact on farming in UK
- Some crops may be easier to grow, and the growing season will expand.
- However, more droughts will disrupt the growing season. Some of crops we grow today may not be suited to higher temperatures, too.
Noticeable trends from climate change in UK
- 7 of the last 10 summers (2011-2020) have reached a temperature of 34°C
○ Before this, just 7 of the previous 50 summers (1961-2010) reached 34°C - 6 of the 10 wettest years on record have been since 1998
Pos and neg impacts of climate change on UK
Positives
Opening of Arctic navigation, improving transport and trade with asian countries (at the expense of polar bears) - econ
Trees and plants flower earlier - more co2 can be absorbed and an increased growing season (higher yield) and more biodiversity in Spring. They can also be grown in more places. - environ
Increased tourism as more people stay or travel to the UK - econ, soc
Fewer cold related deaths - soc
Negatives
Cairngorms ski resorts may have to close (scottish resort) - soc, econ
Thames Barrier needs replacing as sea levels rise - costs a lot more - soc, econ, environ
Higher flood risk and floods get more severe as well as frequent - soc, environ
Some animals migrate - loss of wildlife - environ
Tuvalu Location
A group of 9 islands in the South Pacific. Directly east of Papua new guinea and directly north of Fiji and north-east of Australia. Low lying islands, highest point on the islands is only 4.5m above sea level. It is an atoll and it is part of ‘SIN’ - small island nations that are under risk from climate change, identified by the UN.
Other: The economy is based on the export of copra (part of a coconut) and the sale of tuna (and the sale of postage stamps)
Issues and explanations with Tuvalu
Increased sea level Rise -> it will flood the island (inundation - flooding), max altitude is 4.5m.
Transport links are in danger ->runway is under threat of flooding, roads get flooded during high tides and storms
Salt water intrusion + droughts-> pollutes soil and also (less) drinking water. So, less water supply and there are already no rivers as water gets soaked up by rocks; Water comes from wells
Rising sea levels-> coastal erosion is reducing the area of the island. They also have less area for agriculture which leads to them having less money.
