A Quick Overview of the UN Special Report on Global Warming of 1.5C
The Report
The United Nations climate report that was released in fall 2018 has deservedly received a lot of attention. Let’s talk a little bit about what was in it!
The UN Special Report on Global Warming of 1.5℃ was just the first in a series of 3 Special Reports being released before 2020. This first report was important because we are running quite low on time to act if we are to reach the goals of the Paris Agreement. The goal of the Paris Agreement is to hold the global average temperature increase to below 2℃ and to pursue efforts to limit it to 1.5℃. Our greenhouse gas emissions are currently bringing us perilously close to the 1.5℃ reach goal so this report sought to lay out what is needed to limit warming to 1.5℃, what the differences between a 2℃ vs. 1.5℃ world are, strengthening the global response, and how combating climate change relates to the UN Sustainable Development goals. The report is not new research, rather it is a synthesis of 6,000 peer reviewed studies that were reviewed and synthesized into the report by dozens of scientists from around the world. It represents the very best of our collective knowledge on global warming.
Impacts
There is no safe level of warming. What we are facing at this moment is already unacceptable. Currently the planet has warmed by about 1℃ above what surface temperatures were before we started releasing large quantities of greenhouse gases. Due to the climate system taking time to catch up to emissions we are currently experiencing effects of warming, such as increased wildfires, hurricanes, and heatwaves, from when the planet was about 0.1–0.23℃ cooler.
The severity of impacts is not in proportion to emissions, rather the severity often grows quicker, and many impacts are irreversible. This means that the half a degree difference between 1.5 and 2℃ is substantial. Let’s take a quick look at some of the impacts of that 0.5℃ difference would be.
That half a degree difference means more than twice as many people would be living with severe heat waves every 5 years- that translates to about 420 million more people being affected. The percentage of vertebrates, plants, and insect species projected to lose half their range is 2–3x greater for 2℃ than for 1.5℃- that is a lot more species and ecosystems which would be impacted.
Sea level rise will continue throughout the century, and likely beyond, regardless of emissions pathways. Limiting warming to 1.5℃ would see 10 million fewer people impacted by rising seas. Sea level rise projections are also uncertain due to the tipping points for the Greenland and Antarctic ice sheets being poorly constrained, however they are thought to be somewhere between 1.5–2℃. So depending on stability of the ice sheets sea level rise projections could change locking us into larger rises in sea level.
None of that is good news, but rather then let it freeze us with fear it should motivate us to push harder for change.
Sustainable Development Goals
The impacts of climate change are not felt equally by all people. Already vulnerable populations are expected to be hardest hit including people living in poverty, homeless populations, some indigenous peoples, and people living in coastal regions. Regions especially impacted include the Arctic, desert regions, and low lying island nations.
Climate change is also expected to exacerbate poverty as people are forced to respond to multiple impacts at once. For instance, communities could be fighting increased mosquito-borne illnesses alongside responding to ongoing drought and crop failures. Therefore the solutions to climate change need to center the needs of the most vulnerable populations. Adaptation and mitigation measures need to be community specific to ensure that people’s needs are met and the people least responsible for emissions are not further burdened by efforts at mitigation. With emphasis given to social justice and equity the solutions to climate change can make a better world for everyone and can aid in reaching the UN Sustainable Development Goals.
Emissions Reductions
Greenhouse gas emissions come primarily from the burning of fossil fuels for energy and transportation. They are also from agriculture (especially animal based agriculture), cement production, and more. They change the composition of our atmosphere and trap heat leading to the rise in global temperatures and cascading effects such as the ones mentioned above. We need to stop emitting them in order for the climate system to recover, and we need to do it soon.
The reductions needed are massive and they will take bold action, not incremental change. If emissions reductions had begun decades ago we could have had a smoother transition, but, for a variety of infuriating reasons, they weren’t. In order to stay below a 1.5℃ temperature increase we need to reduce emissions by 45% below 2010 levels before 2030. After that, emissions would need to reach net zero by 2050. The report does not say that all hope is lost if emissions aren’t adequately reduced within 12 years of the report’s publication. Rather, it says that 1.5℃ above preindustrial levels will almost certainly not be attainable unless dramatic emissions reductions are implemented immediately. It is a wakeup call for us to reduce emissions now so that the impacts we are currently facing don’t become far worse than they will already be.
But emissions are not currently reducing. In fact they are rising and rose again last year. Since emissions have risen since 2010 we actually need >50% reductions below 2018 levels…and now we need to do it in 11 years.
Strengthening the Global Response
Unfortunately the global community is not on track to meet the Paris Agreement goals. The current pledges from various countries combine to put us on track for 3+℃ warming by the end of the century, even assuming the plans are perfectly implemented. Strengthening the response requires redoubling our efforts to reduce GHG emissions, alongside adaptation to reduce the harms already being experienced.
Mitigation include things like phasing out coal use, increasing the share of energy provided by renewables, decreasing industrial emissions, moving towards plant based diets, increased support for public transportation, and much more. Adaptation includes protection from extreme heat and flooding, forest protection, wetlands protection, and the creation of urban parks. These are all great things! This isn’t a tedious list of boring policies, this is a blueprint for a better future. Building renewable energy infrastructure will create jobs and will lead to better air quality. Creating urban parks will reduce the heat island effect that plagues cities, and give communities beautiful spaces in which to gather. More public transportation will reduce congestion in cities and give people greater mobility. These are all wonderful things that we can look forward to!
It is a challenge, and one of the biggest we will ever face, but it is also an opportunity to create a better world.
References:
If you like to read the UN report yourself it is freely available to the public here (and linked above as well).
The Climate Action Tracker website that produced the second plot is another great resource. You can see it here.
