Hey guys Julia here for DNews Coming up in December of 2015, the UN willhost the 21st Conference of Parties in Paris. The focus of this year’s COP21 will be climatechange. Most of the leading nations in the world have been asked to pledge to keep therise in global temperature under 2 degrees celsius. It’s clear that a sharp curb inco2 and greenhouse gas emissions is needed. Unfortunately, not all countries agree onhow best to go about that. There’s two main plans: one says everyonegets a per capita cut. Everyone, all nations, have an equal responsibility to curb emissions.The other says that countries who polluted more in the past have more responsibilityto curb their emissions, so that those that polluted less can have some wiggle room tostill grow. But one study from the Center for InternationalClimate and Environmental Research – Oslo (CICERO) found that the US, EU, and Chineseemission pledges leave very little room for other countries to emit in a 2°C world.
Thosecountries say their pledges are “fair and ambitious” but might not be enough to keepthings cool enough. The 2 degrees target was decided back in 2009at another UN conference in Copenhagen, where in the Copenhagen Accord countries recognized“the scientific view that the increase in global temperature should be below 2 degreesCelsius”. But why did they choose that number? Well that number can be traced back to twopapers published in the mid-70s by Professor of Economics William Nordhaus at Yale University.In these papers he said that “If there were global temperatures more than 2 or 3° abovethe current average temperature, this would take the climate outside of the range of observationswhich have been made over the last several hundred thousand years”. Ice core sampling in the mid 80s confirmedthat two degrees above pre-industrial levels hadn’t been seen on the planet in at leastthe last 100,000 years. Another report in the early 90s reconfirmed that the consensusthat two degrees is “an upper limit beyond which the risks of grave damage to ecosystems.
are expected to increase rapidly”. Since then, that number has had huge visibilityas a “speed limit” of sorts. As we might pass that number, the worse effects on theclimate and the faster those effects will happen. Effects like global sea level rise. A studypublished in the journal Nature Climate Change found that levels could rise 1.5 and 4 metersby the year 2300 if the Earth warms at least 2 degrees. The effects of which we’ve talkedabout in previous episodes. Links for those down below. Not only could oceans rise, but rivers couldrun dry, according to a study published in the journal Philosophical Transactions ofthe Royal Society A. In analyzing water scarcity, researchers found that water supplies woulddwindle thanks to more pressure from a growing population. If the temperatures climb evenhigher, to four degrees, some river beds will be drier but some might be wetter, which couldput more pressure on stressed out governments.
As the temperatures get worse, the effectswill be more extreme. In another study also published in the samejournal, researchers found other effects include no sea ice in the arctic in the summer, coralreef die outs, melting of permafrost which will release more greenhouse gases into theatmosphere, and “die-back of the Amazon forest”. The study also predicts that semi-aridand arid places, like sub-Saharan Africa will be even drier, they predict the collapse ofthe agricultural system in that region. So it’s safe to say that if the world warmsup, as it looks like it very well might, Earth is going to look a lot different. We’re witnessing one of the effects of aclimate change right now! Arctic ice levels have been the lowest scientists have everseen. So what happens if all the ice melts? What changes have you noticed, perhaps longersummers?