Our climate is changing! This in itself is not shocking nor surprising. Over geologic history, the global climate has always changed with warmer and cooler periods than the present period. The past 600.000 years we have had four glacial periods with large parts of Europe covered by ice and three interglacial warmer periods. Technically, at present we are at one such warmer interglacial periods. Carbon dioxide, CO2 concentration in the atmosphere and temperature have tracked closely over the last over the past 300.000 years as concluded from ice core analysis of the Antarctic. However, since industrialization this correlation has been lost due to the human-induced excess of CO2 emission to the atmosphere. The most optimistic climate scenario predicts a 4-degrees temperature increase relative to present day while the most pessimistic climate scenario results in 12 degrees of warming in 2100. If we do not act now (https://www.ipcc.ch/report/ar5/).
In Paris in 2015 politicians signed the so-called Paris Agreement during the COP21 meeting (http://www.undp.org/content/undp/en/home/presscenter/events/2015/december/COP21-paris-climate-conference.html). In the Paris agreement, for the first time in over 20 years of UN negotiations, countries ratified an agreement ‘to achieve a legally binding and universal agreement on climate, with the aim of keeping global warming below 2°C.’ This 2°C is about the level of warming reached after the start of industrialization.
COP21 is an agreement to undertake ambitious efforts to combat climate change and adapt to its effects, with enhanced support to assist developing countries to do so. In summary:
- Global temperature rise this century well below 2°C above pre-industrial levels;
- Pursue efforts to limit the temperature increase even further to 1.5 °C;
- Increase the ability of countries to deal with the impacts of climate change;
- Making finance flows consistent with a low GHG emissions and climate-resilient pathway
Over 90% of CO2 emission to the atmosphere is from fossil fuel burning. A back of the envelope calculation learns that if we continue emissions at the present pace we will have reached this maximum CO2 concentration by 2050. Thus we have 30 years to make our energy production CO2 neutral which requires a massive transition from fossil fuels to renewables; the energy transition. This is a wicked problem, as it does not only imply energy transition towards renewables but this in the context of an ever-increasing demand of energy with the increase of global population. It is predicted that the energy demand in 2035 will be double that in 1990. Energy transition is one solution, however CO2 capture and storage is an option that the Dutch government is seriously considering. CO2 is captured at the source, compressed and transported through pipelines and stored in geological (former oil and gas) reservoirs. This may have some environmental issues associated with it such as the risk of fault (re-)activation and potentially causing both leakage and induced seismicity and the fact that CO2 partially dissolves in time thereby potentially increasing the acidity of the water.
Global warming has resulted in additional challenges our planet is facing. The ESA Cryosat satellite mission has shown that the Arctic sea-ice extent has shrunk by 12% per decade since 1978. Satellite missions such as NASA’s OMI and ESA’s Tropomi allow to measure atmospheric constituents related to air pollution at detail and link them directly to potential sources of the pollution showing increases in various greenhouse gases in the atmosphere. A global network of tide gauges has revealed the increase of sea-level height throughout the 20th century because of thermal expansion of the upper layer of the ocean was in the order of 1,5 to 2 mm/year. Systematic monitoring of the sea level with altimeters started with the NASA TOPEX/Poseidon mission in 1992 and continued with the Jason-1 and Jason-2 missions which confirm sea level rise producing global mean sea level maps every 10 days. Sea level rise not only causes inundation and shoreline erosion, but may also have an effect on various water-borne diseases. Extreme weather events have been attributed to global warming and many scientific studies predict that more extreme weather events will occur with increasing global temperatures. More floods, more heat waves, more droughts, more tropical cyclones. In addition, our vulnerability to such events changes as the world population is growing, urbanization takes place in coastal zones, floodplains and through the occupation of marginal lands.
-  (https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/cryosat)
-  (http://www.tropomi.nl/)
-  (https://sealevel.jpl.nasa.gov/missions/topex/)
-  (https://www.un.org/sustainabledevelopment/sustainable-development-goals/)
-  (https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/01001.pdf)
-  https://www.planete-energies.com/en/medias/infographics/world-energy-mix-1990-2035-2degc-target
-  https://www.carbonbrief.org/seven-charts-show-new-renewables-outpacing-rising-demand-for-first-time.
Freek van der Meer (University of Twente) – GEOCAP project leader