Climate change is happening now and will affect all of us. Even if we cut our emissions of carbon dioxide (CO2) by 60-90% today, as recommended by international scientists, we still won’t escape the effects of the massive increase in CO2 in the atmosphere that we have already created. We can’t say exactly what the impact of these emissions will be, especially at the local level, but we can make predictions and construct reliable models that give us likely scenarios.
Page contents:
- Water: rising tides and increasedscarcity
- Agriculture: hunger and loss
- Disrupting ecosystems: climate change tokill up to 1 million species
- Changing weather patterns: creatingunnatural disasters
- Human health: disease
- A vicious cycle
1. Water: rising tides and increased scarcity
The temperature of the world’s oceans is rising. This rising heat will cause the sea water to expand, raising tide levels, causing coastal flooding especially in low-lying river delta and island areas. It is predicted that this combined with the extra water released from melting glaciers and ice caps will cause a 15-95cm rise in sea levels by 2100 on top of the 10-25cm already experienced.
A barbeque outside a community building in Tuvalu.
Young men having a barbeque outside a community building in Tuvalu,
whilst knee-deep in water. Rising sea levels are leading to
increasingly high tides on these tiny coral atolls.
Photo credit: MarkLynas
- This is enough to submerge many low-lying island nations entirely — one of the Carteret atolls of Papua New Guinea has already been cut in half by the ocean.
- Tuvalu in the South Pacific has concluded a deal with New Zealand to evacuate the entire 10,000 population. For now, only 75 people per year will leave the islands.
- Between now and 2020, up to three-quarters of the world’s population, most of them living in poor countries, could be at risk from drought or flood
- A 50 cm rise will bankrupt Venezuela
- A 1 metre rise will displace 80% of Guyana’s population
- Many developing countries have their main cities in coastal areas, so these will be the first to go, causing a devastating destruction of infrastructure in those countries least able to deal with it.
Bangladesh:
In September 1998 two thirds of this Asian country was submerged by major floods. Twenty one million people were left homeless. On current predictions, a fifth of Bangladesh will be drowned entirely and the rest regularly experience floods on the scale of 1998 by 2100.
Flooding will be exacerbated by exaggeration of the world’s rainfall patterns. This means that wet areas will become wetter, but it also means dry areas will become drier. Water scarcity for drinking and industry is already a problem for 1.7 billion people. By 2050, it is likely to be a problem for up to 3.6 billion, with Lake Chad already 95% disappeared, and other sources likely to dry up. This raises the possibility of water wars, and desperation for billions of people.
2. Agriculture: hunger and loss
The lack of rain in drier areas will soon negate any of the positive effects of more CO2 (increased plant growth), and it is probable that we will see the same kind of massive crop failures experienced in northern Africa recently spreading around the world. Drought could become a permanent state for countries like Somalia. This means hunger, famine and severe food shortages.
Flooding, expected to wipe out the one third of the world’s crop lands that are in coastal or low lying areas, will also have a major impact. Floods in Mozambique in 1998 during El Nino wiped out all ‘plant genetic resources’ according to the UN Food and Agriculture Organisation, causing terrible stress on food resources. The Hadley centre predicts 30 million more people will be hungry because of climate change by 2050, with 300 million in sub-Saharan Africa suffering from chronic malnutrition by 2010.
3. Disrupting ecosystems: climate change to kill up to 1 million species
Photo taken in 1980 of a glacier at the top of Jacabamba valley, in the eastern Cordillera Blanca, Peruvian Andes.
Photo credit: Bryan Lynas
The same place twenty years later - the glacier has melted; concrete evidence of global warming. Note also the severe thinning of the icefield on the skyline above the lake.
Photo credit: Tim Helweg-Larsen
Scientists at Leeds University predict that over the next fifty years, climate change could drive a quarter of land animals and plants into extinction. More than 1 million species could be lost by 2050. Much of that loss - more than one in ten of all plants and animals - is irreversible, because of the greenhouse gases already in the atmosphere.
As the earth heats up, climate zones will shift outwards from the equator. This means that countries to the north of the equator like the UK will find themselves living in the recognisable climate of countries far closer to the equator, as will southern countries like New Zealand. Within our lifetimes, London may have the climate of southern France, while the scorching deserts of northern Africa may creep into Europe. Per degree centigrade rise in world temperatures, zones will move approximately 300 km outwards.
In 1998, sunfish and seahorses were seen for the first time in the warming waters off the British coast, and unconfirmed sightings of two great white sharks off Cornwall this year have led to concerns that this disruption to the ecosystem is happening faster than expected. Vast swathes of the earth may become empty of life. The golden toad of Costa Rica is already described as climate change’s first known victim. This species has become extinct due to the loss of habitat caused by climate change. Birds, which have the greatest chance of escape, could in theory move to a more suitable climate, but the trees and other habitat they need for survival are unlikely to keep pace.
See
- Science News: ‘Mountain creatures prove extra-vulnerable’ (August 16, 2003)
- GuardianUnlimited: ‘An unnatural disaster’ (January 8, 2004)
4. Changing weather patterns: creating unnatural disasters
More energy from the sun trapped in the weather system by CO2 emissions means the exaggeration of its force and unpredictability. The kind of disasters already seen are likely to take increasingly extreme forms, with storm surges and prolonged droughts added onto hurricanes and cyclones, as the extra energy whips up the system.
Hurricane Mitch
In October/November 1998, 10,000 people died in Honduras and Nicaragua as hurricane Mitch hit people with 155 miles per hour winds. Three million people were displaced, and the cost of the damage totalled 70% of Honduras’ income.
This will cause massive damage to infrastructure and lives. The UN predicts that 25 million environmental refugees were created in the 1990s, with no official status, forced from their homes by ‘natural’ disasters exacerbated or caused by climate change. The New Economics Foundation suggests that the cost of paying for human-caused ‘natural’ disasters could overtake the income of the world economy by 2065. According to Munich Reinsurance, during the 1960s there were 16 climate-related natural disasters. During the 1990s there were 70.
El Niņo
The El Niņo phenomenon, which causes extreme weather conditions, used to occur every seven years on average. In 1982-3 it brought the most serious conditions ever seen, causing $8 billion damage and 1000 dead. But from 1991 to 1995 some kind of El Niņo occurred every year, and re-appeared in 1998 with torrential rains, droughts and flash floods See Impactsof El Niņo and benefits of El Niņo prediction for general info on El Niņo
5. Human health: disease
In hotter, wetter temperatures, diseases thrive. Malaria and other insect borne diseases are expected to massively increase their spread and range as more humid weather allows previously untouched countries to experience so-called ‘tropical’ diseases, and those already suffering are hit harder. It has been suggested that 60% of the world will be in a malaria zone by 2100. Rift valley fever has already been seen to jump species to infect humans in times of great heat and water pressure, and this is a danger for other infections too. As flooding and habitat damage encourage shifting populations, disease will be even further spread, and overcrowded city slums extend further. Malnutrition from food scarcity, and the lack of water, is also likely to have a major impact on human health.
For detailed descriptions of the impact of climate change on the world’s population:
- Friends ofthe Earth: Climate General Readers (see ‘Gathering Storm — the human cost of climate change’)
6. A vicious cycle
More frightening even than these likely impacts, is the possibility of what is called ‘positive feedback’. This is when the increase in greenhouse gases causes other, less predictable reactions than simple heating, reinforcing and accelerating the impact of the changes outlined above. It is even possible that extreme and unanticipated changes may occur, causing dramatic and catastrophic shifts.
Some possible examples of this are:
The Big Melt
The world’s ice caps are already melting. There has been a 40% drop in the amount of arctic ice since the 1970s. Were this effect to spread, and the northern ice fields melt, a rise in sea levels of up to seven metres would occur. This would not simply overwhelm low-lying countries like Bangladesh, but also major western cities such as London, Rome and New York.
Permafrost
Permafrost covers around 450 billion tonnes of carbon stored in dead vegetation. Were this to melt, that massive carbon store would be uncovered, and the level of CO2 in the atmosphere would increase dramatically.
Water evaporation
As the seas heat up, more surface water will evaporate. Since water vapour is in itself a natural greenhouse as, this will thicken the ‘greenhouse’ further, and re-enforce the damage done by CO2.
Losing the forests
Not only does the destruction of forest areas mean less capacity to convert CO2, but the act of burning the plant life to make way for agricultural land releases massive amounts of CO2 into the atmosphere, as trees are natural sources of carbon. Modelling by the Hadley centre suggests that due to changing climate, forests such as the Amazon may experience dieback, and thus become net contributors of carbon to the atmosphere as the forest burns or decays. This again has a multiplication effect.
- Global Warming: Early WarningSigns
- Climate Change: A Welfare Economics Perspective: Damages of ClimateChange
- UKClimate Impacts Programme: The future UK climate
- Intergovernmental Panel on Climate Change: The Regional Impacts ofClimate Change
- The Tyndall Centre for Climate Change Research: ‘EmissionsScenarios — What are they and what do they tell us?’