Humanity and life on Earth now face a ‘direct existential threat’
The world must act swiftly and robustly to keep global warming under 1.5°C and try to avoid utterly catastrophic impacts to life on Earth.
Human activity is causing irreparable harm to the life on this world. A mass extinction event, only the sixth in roughly 540 million years, is underway. Many current life forms could be annihilated or at least committed to extinction by the end of this century.
The air we breathe, the water we drink, the earth we plant in, the food we eat, and the beauty and diversity of nature that nourishes our psychological well-being, all are being corrupted and compromised by the political and economic systems that promote and support our modern, consumer-focussed lifestyles.
We must act while we still can. What we are seeing now is nothing compared to what could come.
Effects on global human society, if the climate and ecological emergency is not addressed, may spiral out of control.
But our leaders are failing in their duty to act on our behalf. Our current systems of governance is compromised by a focus on profits and economic growth. Politicians can be influenced by lobbies of powerful corporations and the media are hampered by vested interest of corporate advertisers undermining our democratic values.
We have run out of the luxury of time to react incrementally.
We must radically and immediately begin reducing emissions and improving carbon absorption, drawing it down and locking it up again.
Only a peaceful planet-wide mobilisation of the scale of World War II will give us a chance to avoid the worst case scenarios and restore a safe climate/
The task before us is daunting but big changes have happened before.
Let’s make a better world.
In 1992, the Union of Concerned Scientists including the majority of living science Nobel laureates, penned the “World Scientists’ Warning to Humanity” calling on humankind to curtail environmental destruction and warning that “a great change in our stewardship of the Earth and the life on it is required, if vast human misery is to be avoided.” They showed that humans were on a collision course with the natural world. They proclaimed that fundamental changes were urgently needed to avoid the consequences our present course would bring.
The authors of the 1992 declaration feared that humanity was pushing Earth’s ecosystems beyond their capacities to support the web of life. They described how we are fast approaching many of the limits of what the biosphere can tolerate without substantial and irreversible harm. They implored that we cut greenhouse gas (GHG) emissions and phase out fossil fuels, reduce deforestation, and reverse the trend of collapsing biodiversity.
In 2017, humanity was given a second notice. Over 15,000 scientists signed a new and even more urgently worded letter which warned that “To prevent widespread misery and catastrophic biodiversity loss, humanity must practice a more environmentally sustainable alternative to business as usual. This prescription was well articulated by the world’s leading scientists 25 years ago, but in most respects, we have not heeded their warning. Soon it will be too late to shift course away from our failing trajectory, and time is running out. We must recognize, in our day-to-day lives and in our governing institutions, that Earth with all its life is our only home.”
Over 50% of the human addition of carbon to the atmosphere through the burning of fossil fuels has occurred in the last 25 years – i.e. since the IPCC was founded.
Human activities have caused the planet’s average surface temperature to rise about 1.1°C since the late 19th century. Most of the warming occurred in the past 35 years.
A 2018 study shows how deadly heat waves may limit habitability of one of the world’s most populous regions in the world. Concluding that continued burning of fossil fuels would lead to lead to heat extremes that exceeded “the threshold defining what Chinese farmers may tolerate while working outdoors.”
Climate change in your lifetime…
A biological annihilation of wildlife in recent decades means the Sixth Mass Extinction in Earth’s history is under way.
Globally species are going extinct at rates up to 1,000 times the background rates typical of Earth’s past. The direct causes of biodiversity loss being habitat change, overexploitation, the introduction of invasive alien species, nutrient loading and climate change.
The average rate of vertebrate species loss over the last century is up to 100 times higher the background rates typical of Earth’s past. The direct cau than the background rate. The total number of vertebrate species that went extinct in the last century would have taken about 800 to 10,000 years to disappear if the background rate had prevailed.
The latest Living Planet Index shows an average decline of 60% in population sizes of thousands of vertebrate species around the world between 1970 and 2014.
More than a quarter of the assessed species (around 100,000) are threatened with extinction . That is 40% of all amphibians, 25% of all mammals, 34% of all conifers, 14% of all birds, 33% of reef-building corals, 31% of sharks and rays.
Corals reefs are suffering mass die-offs from heat stress . These events are becoming much more common with back to back die-offs on the Great Barrier Reef in Australia in 2016 and 2017. The predictions are that at even at 2C of warming these heat waves will occur on an annual basis .
Prof. Ove Hoegh-Guldberg directs the Global Change Institute at the University of Queensland.
Catastrophic reductions in global insect populations have profound consequences for ecological food chains and human crop pollination.
There is strong evidence that many insect populations are under serious threat and are declining in many places across the globe. Multiple pressures might include habitat loss, agro-chemical pollutants, invasive species and climate change.
A 27-year long population monitoring study in Germany revealed a dramatic 76% decline in flying insect biomass. And a new study by Dutch scientists found that Butterfly numbers had fallen by over 80% in the last 130 years. With the authors concluding that " industrial agriculture is simply leaving hardly any room for nature ."
One of the world’s leading medical journals, The Lancet, carried out a major review which concluded that climate changed posed “ the biggest global health threat of the 21st century ” because of both the direct impacts of extreme weather events and the indirect disruption to the social and ecological systems that sustain us.
More frequent and severe water extremes, including droughts and floods, impact agricultural production, while rising temperatures translate into increased water demand in agriculture sectors.
The number of extreme climate-related disasters, including extreme heat, droughts, floods and storms, has doubled since the early 1990s , with an average of 213 of these events occurring every year during the period of 1990–2016. These harm agricultural productivity contributing to shortfalls in food availability, with knock-on effects causing food price hikes and income losses that reduce people’s access to food.
Risk of extreme weather hitting several major food producing regions of the world at the same time could triple by 2040 (1 in 100 year event to 1 in 30).
A recent study looking at the impact of climate change on food production for the top four maize-exporting countries , which currently account for over 85% of global maize exports, found that “the probability that they have simultaneous production losses greater than 10% in any given year is presently virtually zero, but it increases to 7% under 2°C warming and 86% under 4°C warming “
Water withdrawals grew at almost twice the rate of population increase in the twentieth century.
The global water cycle is intensifying due to climate change, with wetter regions generally becoming wetter and drier regions becoming even drier. A 2018 UN report highlights that at present, an estimated 3.6 billion people (nearly half the global population) live in areas that are potentially water-scarce at least one month per year, and this population could increase to some 4.8–5.7 billion by 2050.
Rising temperatures will melt at least one-third of the Himalayas’ glaciers by the end of the century even if we limit the temperature rise to 1.5°C. Melting glaciers in both the Andes and the Himalayas threatens the water supplies of hundreds of millions people living downstream.
A severe drought in Cape Town in 2018 led to severe water restrictions being put in place. The city came to within just days of turning off its water supply – dubbed ‘Day Zero’. Climate scientists have now calculated that climate change has already made a drought this severity go from a one in 300 year event to being a one in a hundred year event. At 2°C of warming a drought of this severity will happen roughly once every 33 years.
Sea level is rising faster in recent decades. Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers and the expansion of seawater as it warms. Sea level rises will cause inundation of low lying land, islands and coastal cities globally.
As sea level rises higher over the next 15 to 30 years, tidal flooding is expected to occur much more often , causing severe disruption to coastal communities, and even rendering some areas unusable — all within the time frame of a typical home mortgage.
2°C warming would threaten to inundate areas now occupied by 130 million people while increase to 4°C could lock in enough eventual sea level rise to submerge land currently home to 470 to 760 million people globally.
The land ice sheets in both Antarctica and Greenland have been losing mass since 2002 . Both ice sheets have seen an acceleration of ice mass loss since 2009. Antarctica is losing six times more ice mass annually now than 40 years ago.
In 2014 a team from NASA found that part of the West Antarctic ice sheet had already begun what they described as an “ unstoppable ” collapse, locking in at least a meter of sea level rise. If we continue warming we will trigger the collapse of more sectors of the ice-sheets.
The oceans are already become 30% more acidic, as carbon dioxide from the burning of fossil fuels dissolves it alters the chemistry of the sea water. On our current emission trajectory, in 2100, the pH increase of the ocean will see a 150% increase in acidity ! This will affect marine life from shellfish to whole coral reef communities by removing needed minerals that they use to grow their shells. The oceanic conditions will be unlike marine ecosystems have experienced for the last 14 million years.
Present ocean acidification is occurring approximately ten times faster than anything experienced during the last 300 million years , jeopardising the ability of ocean systems to adapt.
Scientists are now investigating connections between the huge changes we have seen in the Arctic and changes to the jet stream resulting in increasingly dramatic impacts on extreme weather events at lower latitudes .
All forms of pollution were responsible in 2015 for an estimated 9 million premature deaths —16% of all deaths worldwide—as well as for 268 million disability-adjusted life-years. Pollution is thus the world’s largest environmental cause of disease and premature death .
As the world gets hotter and more crowded, our engines continue to pump out dirty emissions, and half the world has no access to clean fuels or technologies (e.g. stoves, lamps), the very air we breathe is growing dangerously polluted.
Nitrate from agriculture is now the most common chemical contaminant in the world’s groundwater aquifers. These pollutants can also dramatically affect aquatic ecosystems, for example, through eutrophication caused by the accumulation of nutrients in lakes and coastal waters impacts biodiversity and fisheries. Ocean dead zones with zero oxygen have e quadrupled in size since 1950 , suffocating the organisms that live in those areas.
More than 95% of what we eat comes from soil. It takes about 500 years to form 2.5 cm of top soil under normal agricultural conditions.
Soil erosion and degradation has been increased dramatically by the human activities of deforestation for agriculture, overgrazing and use of agrochemicals.
50% of the planet’s topsoil has been lost in the last 150 years , leading to increased pollution, flooding and desertification. Desertification itself currently affects more than 2.7 billion people .
By 2050, land degradation and climate change together are predicted to reduce crop yields by an average of 10 per cent globally and up to 50 per cent in certain regions. Earthworms cannot compensate for the loss of top soil as they too are being depleted by 80% or more from intensive agrichemical fields. Several species of worms are extinct and many others are likely heading that way.