L7- Climate Models Flashcards
(19 cards)
what is radiative forcing
the difference between incoming solar energy absorbed by the Earth and energy radiated back to space
a positive radiative forcong means the earth is gaining energy = warming
why is limiting global warming to 1.5 degrees C important, and why is 2 deg C concerning
limiting warming to 1.5 deg C reduces the risks of extreme weather, sea level rise and biodiversity loss
at 2 deg c the frequency and severity of heatwaves, floods, and droughts increase significantly, posing greater risks to ecosystems and human well-being
why is coupling different types of models beneficial to climate modelling
coupling allows interactions between atmosphere, land, ocean, cryosphere and biosphere to be simulated
captures feedbacks and improves realism in projections of global and regional climate
how can global climate models attribute global warming to human activities
GCMs are run without human influences to simulate natural variability, then with anthropogenic GHG emissions
the differences in outputs helps estimate the human impact on climate
how do lifetimes of components affect global climate and model accuracy
some climate components like CO2 persist for centuries, while others have shorter lifetimes (aerosols)
these differences impact how long changes remain in the system and affect model predications and uncertainty
how can we test if a global climate model is accurate
by hindcasting
running the model to stimulate past climates and comparing it with historical observations
if reproduces known changes, it increases confidence in future projections
what are common sources of error in GCMs
- grid size and resolution
- poor cloud and rainfall simulation
- regional response inaccuracies
- natural variability
- limited representation of processes like the N cycle
how might GCMs be improved in the future
- increase resolution for better regional data
- improve cloud and precipitation modelling
- integrate more earth system components e.g. N cycle
- enhance computing power and data availability
- better parameterisation of small-scale processes
what is the purpose of Representative Concentration Pathways (RCPs)
RCPs describe different future scenarios of GHG emissions and their concentrations, helping model future climate outcomes under various policy and economic conditions
what components do modern GCMs simulate
atmosphere, land surface, oceans and sea ice - often with added biosphere, atmospheric chemistry and cryosphere modules
what do GCMs require as inputs
variables like air temp, pressure, wind, water vapour content, and surface characteristics
how are GCMs structured computationally
earth is divided into a 3D grid of cells across the land, ocean and atmosphere
each grid cell exchanged data with neighbours to simulate interactions over time
what challenges make climate modelling difficult
- earths size and complexity
- regional variation on energy response
- limitations in computational power
- difficulty modelling small-scale or chaotic processes
how have climate models evolved over time
- early models separated land, ocean and atmosphere
- 1990s: coupled models improved feedback and simulation
- 2010s+: biosphere, chemistry and cryosphere models added
what role does model resolution play in accuracy
higher resolution models (more, smaller grid cells) better capture regional detail and small-scale processes but require significantly more computing power
how do models help decision making
by projecting future climate under different scenarios, they inform policies on mitigation, adaptation, resource planning and risk management
how do models simulate anthropogenic impacts
by comparing model runs with and without human influences, we can estimate the impacts of GHG, land use changes and other activities on climate
what natural disasters are intensified by global warming
- heatwaves
- hurricanes and storms
- flooding
- droughts
- wildfires
what actions can help limit warming to 1.5 deg C
- rapid emissions cuts
- renewable energy expansion
- land use changes
- electrification and green tech
- dietary shifts and reduced flood waste
- participatory and integrated mitigation strategies
