Because collective climate action has been delayed until the Paris Agreement was adopted, much more stringent and expensive options are required to hold global average temperature below 2ºC.
The IPCC concluded that the full implementation of GHG emission reduction measures by all countries in all sectors will not be enough to hold global average temperature below 2ºC. Thus, additional measures will be required to cut CO2 emissions to net zero, using technologies to reduce CO2 emissions and to remove CO2 from the atmosphere. The reason to focus on CO2 is that it accounts for 65 percent (or about 35 GtCO2) of global GHG emissions as a result of the burning of fossil fuels34.
One technology to reduce CO2 emissions is carbon capture and storage (CCS). These large-scale industrial plants capture CO2 (from carbon-fueled power plants, refineries, cement plants and steel mills) and store it before it reaches the atmosphere by injecting it deep underground. These CCS plants are expensive, have not been tested at large-scale, and potentially pose risks, such as leakage of CO2 to water, soil or back into the atmosphere. Thus, accelerated research into their financial and environmental viability is needed. Currently, about a dozen CCS plants in the world capture less than 0.1 percent of CO2 emissions (or about 0.036 GtCO2)35.
One technology that could produce energy and remove CO2 from the atmosphere is the production of bioenergy combined with CCS. The production of energy by burning biomass (such as fuelwood and agricultural residues) coupled with CCS could offer negative emissions because the CO2 absorbed by trees and plants during their growth can be captured and stored deep underground. There are risks and challenges associated with these technologies, also known as negative emission technologies, such as competition for food, land and water to grow the necessary biomass to produce bioenergy sustainably, which could negatively impact livelihoods. Other risks are simply not known, because there are currently no large-scale bioenergy with CCS plants in the world36.
The inadequate INDCs have accelerated the need to depend on these technologies. To meet the 2ºC target, global CO2 emissions should be net zero by 2060-207537.
To cut CO2 emissions to net zero requires not only drastically reducing emissions but also increasing the removal of CO2. Currently, the oceans, trees and plants (or carbon sinks) remove about half of anthropogenic (or man-made) CO2 emissions38. Extensive reforestation and conversion of land into forest (afforestation) activities could considerably increase the removal of CO2. But the planting of new forests will not be enough to cut CO2 emissions to net zero because it would imply expanding the current world’s forest cover, at least, twofold. Such massive expansion, though, is constrained by available land. Thus, the large-scale utilization of negative emission technologies will be required. However, the dependence on these negative emission technologies as an option to control climate change is unproven39. Even if new negative emission technologies are developed to remove CO2 from the atmosphere, their impact in controlling climate change will not be immediate –global temperature will continue to increase for decades, after these negative emission technologies are applied40.
The high risks and costs of further postponing decisive climate action, such as the dependence on unproven negative emission technologies, can be reduced by raising the ambition of the INDCs. Taking earlier action will increase the options of feasible and more cost-effective measures to reduce global GHG emissions41, and most importantly, will outweigh the risks and damage costs arising from the changing climate42.
While efforts to reduce GHG emissions are undertaken, the climate will continue to change. Thus, risks due to the impacts of climate change will continue to be felt everywhere. Although some risks are unavoidable43, adaptation measures will lessen the risks and negative impacts on key economic sectors, human health, livelihoods and biodiversity44.
The IPCC analyzed adaptation measures in freshwater resources, food production systems, coastal systems and low-lying areas, urban and rural areas and marine systems. Some examples include rainwater harvesting, improving water management for agriculture, altering cultivation and sowing times for key crops, breeding additional drought-tolerant crop varieties and good-quality, affordable, and well-located housing in urban areas45.
Adaptation is also one of the key elements of the Paris Agreement. Most pledges from developing countries include adaptation plans; however, actions are conditional to the provision of funding for their implementation.
There are many signs that the climate is already changing. Yet some think that climate change is only going to happen by the end of the century. Because of this common misunderstanding, the urgency of climate change has been misunderstood by most.
The end of the century is the timeframe often used by climate scientists to project changes in the average weather (temperature, precipitation and wind conditions) over a long period of time (usually, 30 years). Using climate models, scientists also analyze how the climate is projected to change decade by decade throughout this century.
Climate change is happening now, and much faster than anticipated. The evidence is what most have been experiencing as unusual weather events, such as changes in average rain patterns leading to floods or droughts, more intense storms, heat waves and wildfires, among others daily examples46. Some of these impacts of climate change already had devastating effects on livelihoods, infrastructure and lives.
There is public agreement that a 2ºC increase in global warming should be avoided. In fact, the Paris Agreement set a global average temperature target of well below 2ºC above pre-industrial levels. Some policymakers and civil society groups advocated for a higher ambition target, and a 1.5ºC above pre-industrial levels target was also included. The IPCC has been requested to produce a special report on the impacts, feasibility and costs of the 1.5ºC target.
However, the 1.5ºC target has almost certainly already been missed because of the lack of action to stop the increase in global GHG emissions for the last 20 years. Global average temperature has already reached 1ºC above pre-industrial times in 2015, as reported by the World Meteorological Organization47. This is a significant increase, compared to the 0.85ºC above pre-industrial times in 2012 reported by the IPCC48. An additional warming of 0.4-0.5ºC is expected as a consequence of GHGs that have already been emitted. This additional increase in global temperature is due to the slow response of the ocean-atmosphere system to the increased atmospheric concentrations of GHGs49.
Global GHG emissions are not projected to decrease fast enough, even if all the pledges are fully implemented. Full implementation of the pledges will require the promised US$100 billion per year in financial assistance for developing countries to be realized. As a result, the 1.5ºC target could be reached by the early 2030s and the 2ºC target by 205050.
The main concern is not when the 2ºC target will be exceeded, but the impacts of climate change resulting from such an increase in global temperature. Weather-related events due to climate change have doubled in number since 199051. An increase in global average temperature of 2ºC within the next couple of decades implies an additional doubling in the number of these events.
As the number of weather-related events due to climate change continues to rise, their impact on water resources, food production, human health, services and infrastructure in urban and rural areas, among other sectors52, will be more frequent and intense. Some of the impacts of climate change may be beneficial, while most will not, negatively impacting lives and livelihoods everywhere.
There is still time to slow down the current path towards reaching the 2ºC target within the next few decades. There are two positive aspects towards changing this trend. First, and most importantly, there are still four years before the implementation of the INDCs in 2020. By 2018, all countries agreed to revise their pledges –sufficient time to significantly raise the ambition of actions to reduce GHG emissions and to adopt the necessary policies for their effective implementation in all countries. Second, the IPCC has already committed to improving its communications to make their reports more accessible for the public to understand.
34. IPCC, AR5, WG III, Chapter 1 (2014) ↩
35. IPCC, AR5, WG III, Chapter 1 (2014) ↩
36. IPCC, AR5, WGIII, Chapter 6 (2014) ↩
37. UNEP The Emissions Gap Report 2015 (2015) ↩
38. IPCC, AR5, WG I, Chapter 6 (2013) ↩
39. Betting on Negative Emissions, Nature Climate Change (2014) and UNEP The Emissions Gap Report 2015 (2015) ↩
40. IPCC, AR5, WG I, Chapter 6 (2013) ↩
41. UNEP The Emissions Gap Report 2015 (2015) ↩
42. The Economics of Climate Change, The Stern Review (2006) ↩
43. IPCC, AR5, Synthesis Report (2014) ↩
44. IPCC, AR5, WG II, Summary for Policymakers (2014) ↩
45. IPCC, AR5, WG II, Chapters 3-9 (2014) ↩
46. IPCC, AR5, WG II, Summary for Policymakers (2014) ↩
47. Status of Global Climate in 2015, World Meteorological Organization (2015) ↩
48. IPCC, AR5, WG I, Chapter 2 (2013) ↩
49. IPCC, AR5, WG I, Chapter 12 (2013) ↩
50. IPCC, AR5, WG I, Annex II, Table AII-7-5 (2013) ↩
51. Loss events worldwide 1980 – 2014, Munich RE (2015) ↩
52. IPCC, AR5, WG II, Technical Summary (2014) ↩