In 2009, Johan Rockström led a group of 28 internationally renowned scientists to identify 9 key processes that regulate the stability and resilience of our planet. They proposed quantitative ‘planetary boundaries’ within which humanity can continue to develop and thrive for generations to come. Crossing these boundaries increases the risk of generating large-scale abrupt or irreversible environmental changes.
Let’s break things down…
What are the 9 boundaries?
1. Atmospheric Aerosol Loading – Particle Pollution
This is not yet quantified, though aerosol particles that enter our atmosphere can be very damaging to human health. The boundary was proposed primarily because of the influence of aerosols on Earth’s climate system. Through their interaction with water vapour, aerosols play a critically important role in our water cycles, affecting cloud formation and global / regional patterns of atmospheric circulation, such as the monsoon systems in tropical regions. They also have a direct effect on climate, by changing how much solar radiation is reflected or absorbed in the atmosphere.
2. Biochemical Flows – Nitrogen and Phosphorus
Nitrogen and phosphorus are both essential elements for plant growth, so fertilizer production and application is the main concern. Human activities now convert more atmospheric nitrogen into reactive forms than all of the Earth’s terrestrial processes combined. Much of this new reactive nitrogen is emitted to the atmosphere in various forms rather than taken up by crops. When it is rained out, it pollutes waterways and coastal zones, a threshold we are already crossing.
3. Land System Change
Forests, grasslands, wetlands and other vegetation types are primarily being converted to agricultural land by humans. This activity is undoubtedly behind the serious reductions in biodiversity, and it impacts on water flows and on the biogeochemical cycling of carbon, nitrogen and phosphorus and other important elements. Scientists say that a boundary for human changes to land systems needs to reflect not just the absolute quantity of land, but also its function, quality and spatial distribution.
4. Freshwater Use
The consequences of human modification of water bodies include both global-scale river flow changes and shifts in vapour flows arising from land use change. These shifts in the hydrological system can be abrupt and irreversible. Water is becoming increasingly scarce – by 2050 about half a billion people are likely to be subject to water-stress.
5. Ocean Acidification
25% of the CO2 that humans emit into the atmosphere is ultimately dissolved in the oceans. Here it forms carbonic acid, altering ocean chemistry and decreasing the pH of the surface water. Beyond a threshold concentration, this rising acidity makes it hard for organisms such as corals and some shellfish and plankton species to grow and survive, and losing various species would greatly impact on marine ecosystems. CO2 concentration is the underlying controlling variable for both the climate and the ocean acidification boundaries.
6. Climate Change
We have sadly already passed this planetary boundary due to the levels of CO2 in the atmosphere. We are already losing summer polar sea-ice, and weakening carbon sinks, so really the question now is: how long we can remain over this boundary before large, irreversible changes become unavoidable?
7. Novel Entities – Chemical Pollution
Emissions of toxic and long-lived substances such as synthetic organic pollutants, heavy metal compounds and radioactive materials represent some of the key human-driven changes to the planetary environment. These compounds can have potentially irreversible effects on living organisms and on the physical environment. At present, we are unable to quantify a single chemical pollution boundary, although the risk of crossing Earth system thresholds is considered sufficiently well-defined for it to be included in the list.
8. Biosphere Integrity – Biodiversity Loss
The demand for food, water and resources are the main drivers for change. The current high rates of ecosystem damage and extinction can be slowed by efforts to protect the integrity of living systems (the biosphere), enhancing habitat, and improving connectivity between ecosystems while maintaining the high agricultural productivity that humanity needs.
9. Ozone Depletion
The stratospheric ozone layer in the atmosphere filters out ultraviolet (UV) radiation from the sun. If this layer decreases, increasing amounts of UV radiation will reach ground level. This can cause a higher incidence of skin cancer in humans as well as damage to terrestrial and marine biological systems. Fortunately, because of the actions taken as a result of the Montreal Protocol, we appear to be on the path that will allow us to stay within this boundary.
All information sourced from the Stockholm Resilience Centre.
Mwaka 2009, Johan Rockström aliongoza kikundi cha wanasayansi 28 mashuhuri kimataifa kutambua michakato tisa muhimu ambayo inasimamia utulivu na upinzani wa sayari yetu. Walipendekeza "mipaka ya sayari" ya kiasi ambayo ndani yake ubinadamu unaweza kuendelea kuendeleza na kusitawi kwa vizazi vijavyo. Kuvuka mipaka hii huongeza hatari ya kuzalisha mabadiliko makubwa ya ghafla au yasiyoweza kubadilishwa ya mazingira. Hebu tuvunje mambo chini... Ni nini mipaka tisa? 1. Uwe na mtazamo wa kweli Atmospheric Aerosol Loading <unk> Particle Pollution Hii bado haijathibitishwa, ingawa chembe za aerosol zinazoingia katika anga letu zinaweza kuharibu sana afya ya binadamu. Mpaka huo ulipendekezwa hasa kwa sababu ya uvutano wa aerosoli kwenye mfumo wa hali ya hewa ya Dunia. Kwa njia ya mwingiliano wao na mvuke wa maji, aerosols hucheza jukumu muhimu sana katika mzunguko wetu wa maji, ikiathiri malezi ya mawingu na mifumo ya mkoa wa ulimwengu wa mzunguko wa anga, kama vile mifumo ya mvua ya mvua katika mikoa ya kitropiki. Pia zina athari ya moja kwa moja kwenye hali ya hewa, kwa kubadilisha kiasi cha mnururisho wa jua unaorudishwa au kunyonya katika angahewa. 2. Uwezekano wa kupata Nitrojeni na fosforasi ni vitu muhimu kwa ukuaji wa mimea, kwa hivyo uzalishaji na matumizi ya mbolea ni wasiwasi kuu. Shughuli za kibinadamu sasa hubadilisha nitrojeni ya angahewa kuwa aina za kibiashara kuliko michakato yote ya dunia pamoja. Nyota hii mpya yenye athari nyingi hutolewa angani katika namna mbalimbali badala ya kuchukuliwa na mazao. Mvua inaponyesha, huchafua njia za maji na maeneo ya pwani, kiwango ambacho tayari tunapitia. 3. Uwe na mtazamo wa kweli Mifugo, nyasi, maeneo ya mvua na aina nyingine za mimea hasa ni kubadilishwa kwa ardhi ya kilimo na wanadamu. "Hii ni kwa sababu ya ""mabadiliko makubwa katika utofauti wa kibiolojia na athari kwa mtiririko wa maji na mzunguko wa kibiolojia wa kaboni, nitrojeni na fosforasi na vitu vingine muhimu.""" Wanasayansi wanasema kwamba mpaka wa mabadiliko ya binadamu kwa mifumo ya ardhi inahitaji kutafakari sio tu wingi wa ardhi, lakini pia kazi yake, ubora na usambazaji wa nafasi. 4. Uwe na uhakika Matokeo ya mabadiliko ya binadamu ya miili ya maji ni pamoja na mabadiliko ya mtiririko wa mto wa kiwango cha kimataifa na mabadiliko katika mtiririko wa mvuke yanayotokana na mabadiliko ya matumizi ya ardhi. Mabadiliko hayo katika mfumo wa maji yaweza kuwa ya ghafula na yasiyoweza kubadilika. Maji yanakuwa madogo sana, na kufikia mwaka 2050 watu milioni moja na nusu watakuwa na shida ya maji. 5. Uwe na mtazamo mzuri. Kwa mfano, asilimia 25 ya CO2 inayotokana na binadamu katika anga huyeyuka katika bahari. Huko hufanyiza asidi ya kaboni, ikibadili kemia ya bahari na kupunguza pH ya maji ya uso. Zaidi ya kiwango cha kiwango cha kiwango, acidity hii inayoongezeka hufanya iwe vigumu kwa viumbe kama vile matumbawe na aina fulani za samaki na plankton kukua na kuishi, na kupoteza spishi mbalimbali itakuwa na athari kubwa kwa mazingira ya baharini. Kiwango cha CO2 ni kipimo cha msingi cha kudhibiti kwa ajili ya hali ya hewa na mipaka ya acidification ya bahari. 6. Uwe na uhakika Kwa bahati mbaya, tayari tumepita mpaka huu wa sayari kwa sababu ya viwango vya CO2 katika anga. """Tunapoteza barafu ya bahari ya majira ya joto, na kuharibu sinks za kaboni, kwa hivyo swali sasa ni: tunaweza kukaa juu ya mpaka huu kwa muda gani kabla ya mabadiliko makubwa, yasiyoweza kubadilika kuwa ya lazima?" 7. Uwe na mtazamo gani? Uchafuzi wa kemikali: uzalishaji wa sumu na muda mrefu wa vitu kama vile uchafuzi wa kikaboni, misombo nzito ya chuma na vifaa vya mnururisho huwakilisha baadhi ya mabadiliko muhimu ya binadamu katika mazingira ya sayari. Misombo hiyo inaweza kuwa na athari zisizoweza kubadilika kwa viumbe hai na kwa mazingira. Kwa sasa, hatuwezi kupima mpaka mmoja wa uchafuzi wa kemikali, ingawa hatari ya kuvuka mipaka ya mfumo wa Dunia inachukuliwa kuwa imewekwa vizuri vya kutosha kuingizwa kwenye orodha. 8. Uwe na mtazamo gani? Uadilifu wa Biosphere <unk> Uharibifu wa Biodiversity Mahitaji ya chakula, maji na rasilimali ni madereva kuu ya mabadiliko. Viwango vya sasa vya uharibifu wa mazingira na kutoweka vinaweza kupunguzwa kwa juhudi za kulinda uadilifu wa mifumo ya kuishi (biosphere), kuboresha mazingira, na kuboresha uhusiano kati ya mifumo ya ikolojia wakati wa kudumisha uzalishaji wa kilimo wa juu ambao wanadamu wanahitaji. 9. (a) Kwa nini? Ozoni ya stratosphere (O) ni sehemu ya anga ya juu ya dunia ambayo huondoa mnururisho wa ultraviolet (UV) kutoka kwa jua. Ikiwa tabaka hilo linapungua, kiasi kikubwa cha mnururisho wa UV kitafikia kiwango cha chini ya ardhi. Hii inaweza kusababisha ongezeko la saratani ya ngozi kwa wanadamu na pia uharibifu wa mifumo ya kibiolojia ya nchi kavu na baharini. Kwa bahati nzuri, kwa sababu ya hatua zilizochukuliwa kama matokeo ya Itifaki ya Montreal, tunaonekana kuwa kwenye njia ambayo itaturuhusu kukaa ndani ya mpaka huu. Habari zote zinatoka kwa Kituo cha Uvumilivu cha Stockholm.