Mabadiliko ya tabianchi ni fani muhimu katika sayansi. Hata hivyo, kama sayansi nyingine zote, si sayansi sahihi kabisa. Uelewa wa sayansi za tabianchi daima unabadilika. Mabadiliko ya tabianchi si jambo jipya; daima yamekuwepo, na daima yataendelea kuwepo. Kipindi kinachojulikana kama Enzi ya Barafu, ambacho kilikuwa kipindi cha muda mrefu cha kupungua kwa joto la dunia, ni mfano wa hili.

Climatic change is an important field of study in science. However, as with all sciences, it is not an exact science. The understanding of the climatic sciences is always changing. Climate change is not new, there has always been climate change, and there will always be climate change. The period known as the Ice Age, which was a long-term period of reduction in global temperatures is an example of this.

Ongezeko la joto duniani na mabadiliko ya tabianchi hurejelea kuongezeka kwa wastani wa joto la dunia. Matukio ya kiasili na shughuli za binadamu vinaaminiwa kuchangia ongezeko hili la wastani wa joto la dunia – hili ni eneo la mjadala mkubwa kwa sasa. Hali hii husababishwa hasa na kuongezeka kwa athari ya chafu, ambayo ni ongezeko la joto duniani kwa sababu gesi fulani angani hunasa nishati; gesi kama Kaboni Dioksidi (CO2). Kipindi hiki cha sasa cha ongezeko la joto pia kimelingana na Mapinduzi ya Viwanda, ambayo yalishuhudia kiwango kikubwa zaidi cha CO2 kinachotokana na binadamu, jambo lililowafanya wengi, kama Al Gore, kulinganisha ongezeko la viwango vya CO2 na ongezeko la joto, na kufikia hitimisho kwamba ongezeko la CO2 katika angahewa ya dunia ndilo lililoamua ongezeko la joto. Uhusiano wa CO2 na joto unachukuliwa kuwa chanzo kikuu cha ongezeko la joto duniani; hata hivyo mtazamo huu si wa uhakika kamili, na kuna matatizo kadhaa katika sampuli zilizotumika kufikia hitimisho hilo.

Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to the increase in average global temperatures – this is the area of current considerable debate. This is caused primarily by increases in the greenhouse which is the rise in temperature on Earth as certain gases in the atmosphere trap energy gases such as Carbon Dioxide (CO2). This latest warming period has also coincided with the Industrial Revolution, which saw the greatest output of human induced CO2, leading many, like Al Gore, to compare the rise in CO2 levels with the rise in temperatures, drawing a conclusion that the rise in CO2 in the earth’s atmosphere was the determining factor in the rise in temperatures. The CO2-temperature connection is considered the dominant cause for global warming, however this view is not conclusive and there is a number of issues with the samples used for this conclusion.

Kila baada ya miaka michache, wanasayansi wakuu wa mabadiliko ya tabianchi katika Jopo la Serikali za Kimataifa kuhusu Mabadiliko ya Tabianchi (IPCC) la Umoja wa Mataifa wametoa ripoti kuu zinazoeleza maendeleo ya uelewa wa mabadiliko ya tabianchi. Tangu mwanzo wamekuwa wakipendekeza kupunguzwa kwa uzalishaji wa hewa chafu. Jopo hili linajumuisha mamia ya wanasayansi wa mabadiliko ya tabianchi kutoka kote duniani. Mwanzoni mwa Januari 2007, ripoti kuu ya nne ya IPCC ilifupisha kwamba walikuwa na uhakika zaidi kuliko hapo awali kuhusu mabadiliko ya tabianchi yanayosababishwa na binadamu, kutokana na uelewa bora wa kisayansi: 'Uelewa wa athari za binadamu za kuongeza joto na kupoza kwa tabianchi umeboreshwa tangu Ripoti ya Tathmini ya Tatu (TAR), na kusababisha imani ya juu sana kwamba athari ya jumla ya wastani duniani ya shughuli za binadamu tangu 1750 imekuwa ya kuongeza joto.' Ufafanuzi wao wa "imani ya juu sana" na "inawezekana sana" ni uwezekano wa asilimia 90 wa kuwa sahihi (ripoti yao ya 2001 ilidai uhakika wa asilimia 66).

Every few years, leading climate scientists at the UN’s Intergovernmental Panel on Climate Change (IPCC) have released major reports detailing the progress in understanding climate change. From the outset they have recommended that there be emission reductions. This body is comprised of hundreds of climate scientists from around the world. At the beginning of January 2007, the IPCC’s fourth major report summarised that they were even more certain than before of human-induced climate change because of better scientific understanding; ‘The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report (TAR), leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming.’ Their definition of “very high confidence” and “very likely” is a 90% chance of being correct (their 2001 report claimed a 66% certainty).

Kwa upande wa uzalishaji wa kihistoria, nchi zilizoendelea kiviwanda zinachangia takriban asilimia 80 ya mrundikano wa kaboni dayoksaidi angani hadi sasa. Tangu mwaka 1950, Marekani imetoa jumla iliyojikusanya ya takriban tani bilioni 50.7 za kaboni, wakati China (yenye watu mara 4.6 zaidi)

In terms of historical emissions, industrialised countries account for around 80% of the carbon dioxide build-up in the atmosphere to date. Since 1950, the US has emitted a cumulative total of roughly 50.7 billion tons of carbon, while China (4.6 times more populous)

na India (yenye watu mara 3.5 zaidi) imetoa tani bilioni 15.7 na 4.2 mtawalia. Kila mwaka, zaidi ya asilimia 60 ya uzalishaji wa kaboni dioksidi viwandani duniani unatokana na nchi zilizoendelea kiviwanda, ambako ni takriban asilimia 20 tu ya wakazi wa dunia wanaishi.

and India (3.5 times more populous) have emitted only 15.7 and 4.2 billion tons respectively. Annually, more than 60% of global industrial carbon dioxide emissions originate in industrialized countries, where only about 20% of the world’s population resides.

Ukuaji mkubwa wa utoaji wa hewa chafu katika nchi zilizoendelea unatokana zaidi na ukuaji wa haraka wa viwanda tangu zama za Mapinduzi ya Viwanda. Marekani, yenye uchumi wa dola trilioni 14, ndiyo nchi inayochafua mazingira zaidi duniani, na imekuwa kikwazo kwa makubaliano yoyote ya kuweka malengo ya kupunguza utoaji wa hewa chafu. Kupunguza utoaji wa hewa chafu kungemaanisha viwanda vya Magharibi vingepaswa kuzalisha kidogo; hili lingesababisha uchumi wa nchi za Magharibi kudorora badala ya kukua. Kupunguza matumizi kunachukuliwa kuwa ni 'Shirk' katika Ubepari. Vivyo hivyo, kiwango cha matumizi ya nishati ya mafuta ya visukuku katika nchi zilizoendelea pia ni kikubwa mno ikilinganishwa na sehemu nyingine za dunia. Kupungua kwa rasilimali zisizoweza kurejeshwa na uharibifu wa mazingira kunasababishwa hasa na mifumo ya matumizi ya Marekani. Matumizi ya Marekani ya nishati ya mafuta ya visukuku ni zaidi ya mara tano ya wastani wa dunia.

Much of the growth in emissions in the developed world stem from rapid industrialisation from the industrial revolution era. The US with its $14 trillion economy is the world’s largest polluter and has acted as an obstacle to any agreement on emission reduction targets. Reducing emissions would mean industry in the West would need to produce less – this would lead to economies in the West shrinking rather than growing. To reduce consumption is considered ‘Shirk’ in Capitalism. By the same token, the rate of consumption of fossil fuels in developed countries is also extremely high relative to the rest of the world. The depletion of nonrenewable resources and environmental destruction is primarily caused by the consumption patterns of the US. US consumption of fossil fuels is well over five times the global average.