How do climate systems function, change, and cause hazards? (b) GapFill

In order to predict how the climate will change, we create incredibly complex computer programs called  ensemblesprogrammesfluxesmodels. We feed them past climate data and make assumptions. But we can’t ever fully predict how the climate will change – it’s down to how we behave, and our understanding of the natural world.

Instead, we have to produce a series of different  countriesscenariosA1F1shumans about how much warming will occur based on how our emissions of greenhouse  gasespanesaerosolsgreens might change. We used to use a range of storylines, referred to as the SRES storylines, but now we use a different set called  Ring Carbon PerilRogue Carbon PathwaysRepresentative Concentration PathwaysRepresentative Critical Pathways, or RCPs for short.

For example, we could carry on burning fossil fuels as we are now, or we could substantially decrease our reliance on them. Ideally, we want to stop the current sharp increase in carbon dioxide emissions and corresponding temperature rise. We measure the temperature rise from  1950scurrentpre-industrialindustrial levels. Reducing emissions of greenhouse gases takes a concerted effort by the whole world. As countries  increasedecreaseelectricitydevelop, their wealth increases – energy consumption, food consumption and demand for goods also increase. An increase in the use of fossil fuels such as  coalwindwaterhydro can also occur, a large source of carbon dioxide emissions. However, countries are pulling together to reduce their emissions – by signing up to (ratifying) international  KyotoPariswatersagreements. We don’t fully know how effective their measures will be. The increased use of  thermal stationcoalnon-renewablerenewable power will also help lower the emissions of greenhouse gases. Even individual people can make small changes – such as  flying moreusing the car lessleaving the lights onsending all of our waste to landfill.

While our understanding of the natural world is improving all the time, there are still things that we have overlooked (unknown unknowns!). For example, our models might be over-simplistic or we may not fully understand different processes. Sometimes we discover that things are happening faster than predicted, such as the Greenland  volcanosoilice sheetglass melting faster than anticipated or sudden, irreversible, changes occurring called  adaptationtippingmitigationunder points.